When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I have an 88 NA. I recently rebuilt the intake. While doing this, I also redid the fuel system with AN lines and an adjustable FPR. While redoing the fuel system I had cracked a few of the injector connectors, so I decided to just splice in new EV-1 connectors to the existing harness.
Issue lies here: When I start the car, AWS plugged in, the car will only rev to 2k. My suspicion is that one of the injectors is not firing. Is there a way to test to make sure that all 4 injectors are getting voltage?
If anyone thinks it's not a fuel related issue, I'm all ears. I had initially run it with old spark plugs, and it ran on 1 rotor. The plugs on rotor 1 we're soaked with fuel and the housing was cold. Rotor 2 was hot.
Is it running smoothly? Are there any other issues?
Secondary injectors only fire at >3800rpm, so they won't cause this. It's possible you have an issue with primaries, but I'd check spark too since you indicate one rotor may not be firing at all.
You can check if there is voltage at one terminal of the injector connectors with key to ON, but this is difficult for the primaries with the intake on.
Also, do you mean that the car revs to 2000rpm for 17 seconds then drops down, or that it doesn't perform the 17 second AWS at all?
Is it running smoothly? Are there any other issues?
Secondary injectors only fire at >3800rpm, so they won't cause this. It's possible you have an issue with primaries, but I'd check spark too since you indicate one rotor may not be firing at all.
You can check if there is voltage at one terminal of the injector connectors with key to ON, but this is difficult for the primaries with the intake on.
Also, do you mean that the car revs to 2000rpm for 17 seconds then drops down, or that it doesn't perform the 17 second AWS at all?
When I first start it, the revs come up to 2k and stay there.
When I started it, there was smoke coming from the engine bay so I cut it off immediately. Didn't keep it running long enough to see if it would drop. But, for the brief few seconds it was running, it sounded like it was running on 2 rotors. The smoke from the engine bay is what scares me. I don't have any leaks and it's topped off with 5qts of oil. Perhaps something burning off the headers, but it was a decent amount of smoke...
I have NGK plug wires. Checked the resistance to all of them. Leading is at 7.9 for both, and trailing is at 5.5 and 4.9. They don't seem to be an issue.
When the car is shut off, if you put your head in the engine bay, you can hear a hiss that progressively gets quieter for about 10 secs, until it stops. May be unrelated, but thought I'd mention it nonetheless
When I first start it, the revs come up to 2k and stay there.
When I started it, there was smoke coming from the engine bay so I cut it off immediately. Didn't keep it running long enough to see if it would drop. But, for the brief few seconds it was running, it sounded like it was running on 2 rotors. The smoke from the engine bay is what scares me. I don't have any leaks and it's topped off with 5qts of oil. Perhaps something burning off the headers, but it was a decent amount of smoke...
I have NGK plug wires. Checked the resistance to all of them. Leading is at 7.9 for both, and trailing is at 5.5 and 4.9. They don't seem to be an issue.
When the car is shut off, if you put your head in the engine bay, you can hear a hiss that progressively gets quieter for about 10 secs, until it stops. May be unrelated, but thought I'd mention it nonetheless
So a few thoughts here:
- Smoke is not uncommon after rebuilding the intake since you lose oil, coolant, etc. Maybe have a friend with a hose stand by the engine bay while you run the car to see if the smoke clears up.
- Just after rebuilding the intake you often have carb cleaner and stuff that got into the intake ports. I don't know exactly what you did but I usually use some to clean the mounting area on the engine before putting the intake back on, etc. I wouldn't be surprised if the first start up was stumbly for a few seconds as it clears up.
- The hissing may be fuel pressure bleeding off. If you have an external leak it can cause this, but you'd smell a very strong fuel smell. Otherwise a stuck injector could cause it, but I'd expect it to flood out the rotor. Lastly maybe a bad FPR, but I think it would have to be pretty bad to cause that.
I'd try checking again for obvious leaks (especially fuel and oil) and then start up again with a friend there. Make sure you have oil pressure, and that the coolant gauge starts to move up after a minute or two. As long as you have those two things and no obvious leaks then the rest comes down to tuning the idle.
The factory setup goes:
17 second AWS high idle ~3k, then drops straight to 2-1.5k (thermowax high idle), then over a few minutes it slowly drops progressively to 750.
Also check the two pin connector at the bottom of the rad; if that isn't connected there will be no AWS.
And unrelated, it takes awhile for the OMP lines to fill up, so I'd premix until you see them fill.
- Smoke is not uncommon after rebuilding the intake since you lose oil, coolant, etc. Maybe have a friend with a hose stand by the engine bay while you run the car to see if the smoke clears up.
- Just after rebuilding the intake you often have carb cleaner and stuff that got into the intake ports. I don't know exactly what you did but I usually use some to clean the mounting area on the engine before putting the intake back on, etc. I wouldn't be surprised if the first start up was stumbly for a few seconds as it clears up.
- The hissing may be fuel pressure bleeding off. If you have an external leak it can cause this, but you'd smell a very strong fuel smell. Otherwise a stuck injector could cause it, but I'd expect it to flood out the rotor. Lastly maybe a bad FPR, but I think it would have to be pretty bad to cause that.
I'd try checking again for obvious leaks (especially fuel and oil) and then start up again with a friend there. Make sure you have oil pressure, and that the coolant gauge starts to move up after a minute or two. As long as you have those two things and no obvious leaks then the rest comes down to tuning the idle.
The factory setup goes:
17 second AWS high idle ~3k, then drops straight to 2-1.5k (thermowax high idle), then over a few minutes it slowly drops progressively to 750.
Also check the two pin connector at the bottom of the rad; if that isn't connected there will be no AWS.
And unrelated, it takes awhile for the OMP lines to fill up, so I'd premix until you see them fill.
The car had been run before today. A friend and I were attempting to bleed the coolant system after the rebuild. That's when we had noticed it was running on 1 rotor. But, there was no smoke then.
When I was removing the lower intake manifold, since you can't really see underneath, I accidentally pulled out the exhaust stud instead of the bolt for the manifold. After trying to thread it back in, it stripped out. So I am missing an exhaust stud. Perhaps exhause gasses are slipping past the flange and leaking into the engine bay causing smoke??
As for the hiss, the FPR is brand new, and the injectors were recently serviced. Not sure where the leak could be...
Wanted to update this thread with my newest findings here.
A buddy of mine came over and we poked around the car trying to figure it out. I tried starting it, only to find out it wouldn't turn over. I was somehow flooded. So I pulled both of the necessary fuses and cranked her for a bit to get all the fuel out.
While cranking with no spark or fuel, there was still small amounts of smoke filling the engine bay. Strange. So we popped the fuses back in and started her up. She ran on one rotor again. This time, very very very little smoke.
Spark plugs are brand new, and all plug wires checked for resistance. All good there. Rotor 1 is not running. Because the car was flooded, it leads me to believe that the smoke I was seeing was just excess fuel (which has been premixed) burning on startup.
Now therein lies the question. Why would the engine be flooding after I shut it off?
From what I've read, the most likely culprit is a stuck or leaking injector. But, when I had the intake apart, I rebuilt the injectors. Unlikely that's the issue in my opinion, but there's always a chance the injectors are bad.
Any pointers in the right direction here would be helpful. The fuel setup is as follows:
-Walboro 255 fuel pump-Radium high pressure fuel filter-Fuel lab 515 FPR-Stock injectors and fuel rails-Fuel pressure set to 40psi without vaccum connected
I'm at my wits end. What could be wrong here?
I believe I've found the source of the hiss I had mentioned. It is indeed fuel pressure. Where I adapted the fuel rail to AN, there is a strait fitting that I had put thread tape on. Apparently thread tape was not good enough and I need a washer I presume. It's a slow leak, but its a leak nonetheless. Any other suggestions as to how to stop it from leaking?
Also got a video of the car running. This is a cold start with me keeping the car alive with my foot. Does this sound right?
It sounds like it may be running one one rotor only, but it's hard to tell from a video. It definitely doesn't sound happy.
I'd wait until you have the crush washer in there (I believe you can also get fuel safe threadlocker type sealants too) before really running it again.
In the meantime, have you checked spark? I know you've checked the plugs and wires, but have you used an actual spark checker / timing gun to verify?
It seems based on your earlier description that you have fuel, since you said one rotor was colder and had wet plugs. That may indicate lack of spark.
It sounds like it may be running one one rotor only, but it's hard to tell from a video. It definitely doesn't sound happy.
I'd wait until you have the crush washer in there (I believe you can also get fuel safe threadlocker type sealants too) before really running it again.
In the meantime, have you checked spark? I know you've checked the plugs and wires, but have you used an actual spark checker / timing gun to verify?
It seems based on your earlier description that you have fuel, since you said one rotor was colder and had wet plugs. That may indicate lack of spark.
The video of it running was with brand new NGK plugs. I verified all plug wires are going to the correct plugs. I agree, the engine does not sound happy.
Compression is good on both rotors so I know that's not the issue. I know I'm at least getting fuel to both rotors.
My thoughts are this (and let me know if I'm going in the wrong direction here):
1. Is it possible that I jumped timing? I didn't touch the CAS, but is there something that could have caused it to jump a tooth?
2. If the double throttle valves aren't opening on cold start, could this cause this rough idle? If the check valve that goes from the thermowax to the actuator is backwards or bad, would that cause an issue?
3. If the idle set screw on top of the throttle body is closed (turned all the way clockwise), would that be enough to drop the idle this far?
When I was keeping the car alive with my foot, the throttle was barely responsive. I had to give it a lot to even keep the revs up.
The video of it running was with brand new NGK plugs. I verified all plug wires are going to the correct plugs. I agree, the engine does not sound happy.
That still doesn't tell you if the coils are firing, so unfortunately it's not a surefire thing (pun unintentional). If you don't have a spark checker or timing gun you can pull the EGI fuses, wear thick gloves, and hold the plug threads against the suspension mounting bolts while an assistant cranks. You'll have to check each wire. If you see a spark, you're good. I don't recommend this method as you have a fuel leak and I think it could be dangerous.
Originally Posted by Cardinell
Compression is good on both rotors so I know that's not the issue. I know I'm at least getting fuel to both rotors.
If you have compression and fuel, then spark is the only real option.
Originally Posted by Cardinell
1. Is it possible that I jumped timing? I didn't touch the CAS, but is there something that could have caused it to jump a tooth?
No. The way our timing system works is there is a keyed drive gear on the end of the e-shaft and the main hub is also keyed. The drive gear can't spin on the e-shaft without major damage, nor can the main hub. You'd know if that was a problem.
It is possible to have the CAS inserted wrong but I have been in that position before and both rotors still fired. I can spin the CAS anywhere in its slot or install it one tooth off, and the engine isn't happy about it but both rotors still fire normally.
The CAS will not jump a tooth on its own, again, unless there is catastrophic damage. You'd know.
You can try pulling the cover off the top of the CAS while leaving it in place. Rotate the engine by hand until the pointer is at the yellow (first) mark on the main pulley. This is counter-clockwise as viewed from the front of the car. Then remove the two Philips screws on top of the CAS. There are pictures online of what the gear alignment looks like.
A timing light is required to really dial the timing in, but you will be close enough as long as the CAS is on the right tooth.
Originally Posted by Cardinell
2. If the double throttle valves aren't opening on cold start, could this cause this rough idle? If the check valve that goes from the thermowax to the actuator is backwards or bad, would that cause an issue?
No. In fact, the stock system holds them closed at idle until the car warms up anyways. The double throttle system won't cause this. Case in point, I removed my double throttle system and there is no difference at idle (or any other time, actually).
Originally Posted by Cardinell
3. If the idle set screw on top of the throttle body is closed (turned all the way clockwise), would that be enough to drop the idle this far?
No. You can try winding it out though, there's no harm in playing with the idle bypass screw.
Originally Posted by Cardinell
When I was keeping the car alive with my foot, the throttle was barely responsive. I had to give it a lot to even keep the revs up.
This happened when my last engine was blown on the rear rotor, although obviously you have good compression so that isn't your issue. I'm guessing lack of spark is causing a similar symptom in your case.
That still doesn't tell you if the coils are firing, so unfortunately it's not a surefire thing (pun unintentional). If you don't have a spark checker or timing gun you can pull the EGI fuses, wear thick gloves, and hold the plug threads against the suspension mounting bolts while an assistant cranks. You'll have to check each wire. If you see a spark, you're good. I don't recommend this method as you have a fuel leak and I think it could be dangerous.
If you have compression and fuel, then spark is the only real option.
No. The way our timing system works is there is a keyed drive gear on the end of the e-shaft and the main hub is also keyed. The drive gear can't spin on the e-shaft without major damage, nor can the main hub. You'd know if that was a problem.
It is possible to have the CAS inserted wrong but I have been in that position before and both rotors still fired. I can spin the CAS anywhere in its slot or install it one tooth off, and the engine isn't happy about it but both rotors still fire normally.
The CAS will not jump a tooth on its own, again, unless there is catastrophic damage. You'd know.
You can try pulling the cover off the top of the CAS while leaving it in place. Rotate the engine by hand until the pointer is at the yellow (first) mark on the main pulley. This is counter-clockwise as viewed from the front of the car. Then remove the two Philips screws on top of the CAS. There are pictures online of what the gear alignment looks like.
A timing light is required to really dial the timing in, but you will be close enough as long as the CAS is on the right tooth.
No. In fact, the stock system holds them closed at idle until the car warms up anyways. The double throttle system won't cause this. Case in point, I removed my double throttle system and there is no difference at idle (or any other time, actually).
No. You can try winding it out though, there's no harm in playing with the idle bypass screw.
This happened when my last engine was blown on the rear rotor, although obviously you have good compression so that isn't your issue. I'm guessing lack of spark is causing a similar symptom in your case.
Understood on all the points I raised.
I swapped the leading ignition coil with a known good one and had the same issue. The video is actually with the good coil installed so I can rule that out.
I checked the resistance of all the plug wires and they all seemed fine. But I guess there's no guarantee that they're good. New NGK wires are cheap enough I may buy another set just to rule out the plug wires as well.
Like I said, all plugs are new so they're not the issue.
So I guess the only variable here are the wires.
If that's not it either, is it possible that one of the injectors is stuck open, causing that rotor to continuously flood, and thus wetting the plugs on that rotor?
Then again, you can hear the engine cranks and turns over pretty quickly. If I was on one rotor, wouldn't it take awhile to start?
The rough idle is probably an air leak. . . . . By that, it doesn't have to be a vacuum leak. . . Just air getting where it isn't supposed to go.
You can use the starting fluid method and spray underneath the DVI intake manifold near the EGR valve. . . If you get a slight raise in RPM, and smoothing out the engine for a second or two, you are in the area where it is leaking to air (as it is sucking starting fluid fumes).
You could have an air leak at an injector seal.
But you could also have other air leaks that don't go to atmosphere. The EGR could be stuck open. . The oil injectors could be leaking by. (I'm dealing with that issue now .. .3 out of the four no longer act as check valves to the intake.). . . You could have a bad ACV or BACV (air control valves)
Your EGR valve could be working but your solenoid controlling it could be stuck open.
Get the field service manual at foxed.ca . . It will give you a lot of info to test things.
The $20 hand vacuum pump and a can of starting fluid.. . . .Use them wisely.
My first guess is to always assume an air leak. .. . . If the car has not had it's hoses changed, and are not silicon by now, they need extra scrutiny. .. Remember to twist the hose to break the seal prior to pulling it off.
The rough idle is probably an air leak. . . . . By that, it doesn't have to be a vacuum leak. . . Just air getting where it isn't supposed to go.
You can use the starting fluid method and spray underneath the DVI intake manifold near the EGR valve. . . If you get a slight raise in RPM, and smoothing out the engine for a second or two, you are in the area where it is leaking to air (as it is sucking starting fluid fumes).
You could have an air leak at an injector seal.
But you could also have other air leaks that don't go to atmosphere. The EGR could be stuck open. . The oil injectors could be leaking by. (I'm dealing with that issue now .. .3 out of the four no longer act as check valves to the intake.). . . You could have a bad ACV or BACV (air control valves)
Your EGR valve could be working but your solenoid controlling it could be stuck open.
Get the field service manual at foxed.ca . . It will give you a lot of info to test things.
The $20 hand vacuum pump and a can of starting fluid.. . . .Use them wisely.
My first guess is to always assume an air leak. .. . . If the car has not had it's hoses changed, and are not silicon by now, they need extra scrutiny. .. Remember to twist the hose to break the seal prior to pulling it off.
Entire intake was rebuilt. I replaced all vaccum lines with silicone lines. EGR was tested and holds vaccum. BAC is good, and ACV works too. I would like to smoke test the engine to be sure, but do not have a compressor to do so.
Another update here. Wanted to get everyone's opinion. I took off the UIM to inspect everything. Found a few noteworthy items
I had bought a set of 4 rebuilt injectors. One of them came without the filter in the top of the injector, so I had to run one of my original ones. Does the grommet at the bottom of the injector look correct? The rebuilt one is thinner. Also, there is a lot more space in the tip of the rebuilt one.
Here are the OMP injectors. I take it that it doesn't matter whiche line goes to which injector, as long as they see vaccum
ECU ground was cleaned with a wire brush and covered in dielectric grease. Look correct?
Lastly, there are the hole for the primary injectors. The front looks wet, while the rear looks dry. Could this be a sign of a leaking injector?
Do you recall which injector you took out of which port?
If you are using three rebuilt injectors and one original, I'd suspect the original.
Easy way to diagnose without a testing setup is just to install the two secondary injectors where the primaries were and vice-versa. Then if the car starts and idles but stutters at 4k rpm, you know that one of the ones that was in the primary location was bad.
The OMP setup looks normal. Hard to tell anything from the primary injector diffusers, imo.
Make sure you have the primary air bleed set up as stock. A vacuum line goes from the small nipple on the LIM right by the intake ports to a nipple on the dynamic chamber, I forget which. It helps atomize fuel at low rpm.
Lots of people remove it with emissions deletes and then their idle suffers.
Do you recall which injector you took out of which port?
If you are using three rebuilt injectors and one original, I'd suspect the original.
Easy way to diagnose without a testing setup is just to install the two secondary injectors where the primaries were and vice-versa. Then if the car starts and idles but stutters at 4k rpm, you know that one of the ones that was in the primary location was bad.
The OMP setup looks normal. Hard to tell anything from the primary injector diffusers, imo.
Make sure you have the primary air bleed set up as stock. A vacuum line goes from the small nipple on the LIM right by the intake ports to a nipple on the dynamic chamber, I forget which. It helps atomize fuel at low rpm.
Lots of people remove it with emissions deletes and then their idle suffers.
There are a few vaccum lines that go to the dynamic chamber. I'm not quite sure which one is the air bleed that you mentioned
There are 2 lines on the firewall side of the chamber, 3 on the alternator side, and one on the back by the BAC. Every vaccum line is hooked up, but is there something I should be looking for to see if the air bleed is working?
If the air bleed is hooked up to the appropriate port, it's working. It's basically just a vacuum line that goes to those injector diffusers and provides fresh air.
If you check my stickied thread in this section about rebuilding the intake, it includes a complete vacuum diagram at the end that will show you where everything goes so you can verify it.
While you have your intake off you can check your EGR with a vacuum pump to make sure it isn't leaking too.
If the air bleed is hooked up to the appropriate port, it's working. It's basically just a vacuum line that goes to those injector diffusers and provides fresh air.
If you check my stickied thread in this section about rebuilding the intake, it includes a complete vacuum diagram at the end that will show you where everything goes so you can verify it.
While you have your intake off you can check your EGR with a vacuum pump to make sure it isn't leaking too.
Roger that
Last time I had the EGR off it held vaccum, but that doesn't mean it didn't break between now and then. How many psi or in of HG are you supposed to pull on it?
Last time I had the EGR off it held vaccum, but that doesn't mean it didn't break between now and then. How many psi or in of HG are you supposed to pull on it?
I wouldn't pull more than 5-10psi. It's just a little vacuum controlled valve.
I wouldn't pull more than 5-10psi. It's just a little vacuum controlled valve.
Sounds good. I'll test the EGR and see if that may be causing it. Any downsides to a block off plate?
Also when I attempted to clean the mounting surface between the upper and lower intake manifold, I couldn't get all of the old gasket material off. It had been on there awhile and was hard as a rock. You can see in this picture. To the touch, it's smooth. Not raised at all. That being said, do you think this is enough for the manifold gasket to not seal properly?
There are no functional downsides to the EGR block-off, except emissions related of course. In fact, it's one of the only emissions components you can delete without affecting other things.
That gunk on the manifold flange might be an issue for sealing. I've found that the manifold flanges really want to be as flat and clean as possible. Did you remove the LIM from the engine when you did the rebuild?
There are no functional downsides to the EGR block-off, except emissions related of course. In fact, it's one of the only emissions components you can delete without affecting other things.
That gunk on the manifold flange might be an issue for sealing. I've found that the manifold flanges really want to be as flat and clean as possible. Did you remove the LIM from the engine when you did the rebuild?
If that's the case, then I may just go ahead and delete it all together. It's just another place for a vaccum leak at this point. I assume I use the stock EGR gasket with the block off plate? Or would I use RTV?
So when you had the LIM off you replaced the LIM>Engine gasket. Just checking, that gasket is pressed steel from the factory and leaks a lot.
The easiest way to remove that gunk is to soak the whole LIM in hot water and soften it, but that obviously requires removing the whole manifold to soak it and time to dry it. If in place you can use a razor blade on a scraper, but be careful not to gouge the aluminum or drop the shavings into the engine. It's a pain to do with the manifold installed.
10-21-21, 04:19 PM
