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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.
When I had the LIM off, I did replace it with a new steel multi-layer gasket. Should I have used something else?
I'll give it another crack with a razor and some patience. I think the one I was using before was a bit dull, so I'll try a fresh one
The multi-layer gasket is fine, as long as it's torqued correctly and evenly. The factory ones seem to leak in my experience. Then it's also been 35 years so I imagine a new one is fine. I prefer the blue cork-like gaskets that Atkins sells, because I find them more forgiving. The tradeoff is that they leave behind those deposits when they deteriorate just like you're dealing with now.
The multi-layer gasket is fine, as long as it's torqued correctly and evenly. The factory ones seem to leak in my experience. Then it's also been 35 years so I imagine a new one is fine. I prefer the blue cork-like gaskets that Atkins sells, because I find them more forgiving. The tradeoff is that they leave behind those deposits when they deteriorate just like you're dealing with now.
Gotcha. Yeah I wasn't able to get a torque wrench down there, but I tightened them down progressively by hand, then with a 3/8” drive ratchet. I guess I put about 30 ft/lbs on it.
So I guess next update I will have is after the fuel leak is fixed and the EGR is blocked off. Will also swap the injectors around and see if we get anywhere with it.
Back at it again trying to get this thing running right. So this week I replaced all the spark plug wires with brand new NGK's. I checked for 12V at the coils with the acc on, and verified they are in fact getting 12V. So everything on the ignition side is solid.
Car still won't run right.
I have a known starter ground issue. If I turn the key to the run position, you can hear the fuel pump prime, but the engine doesn't turn over. You have to do it a few times to get it to crank. I've noticed, whenever it does this and it doesn't turn over on the first try, the engine will flood. If I pull the EGI fuses and de-flood it, it still doesn't turn over happily. It'll start for a second and sputter out. I have to pull the spark plugs, dry them off, and re-install. Does the ECU inject fuel, even with the starter not engaged?
Once the spark plugs have been dried and put back in, the engine will start and idle at about 2k (this is with AWS connected). But, If I give it any kind of throttle input, the car will immediately die. It wasn't doing this before, where throttle would cause it to stall out. What could be the issue here? Does this sound like a fuel issue?
AAAAAND with a little more research on my part, I believe I've found the issue for my startup. Not confirmed 100% yet, but I believe this is the issue.
My car is an 88. Has no resistor pack for the injectors, meaning it needs high impedance. I had purchased a set of rebuilt injectors and before checking their resistance, I slapped them on my car. They turned out to be low imp injectors.
Since I don't have a resistor pack in my car, and ran low imps, does that mean my ECU is potentially fried? Or would just my injectors be damaged??
It would take out the ecu injector driver circuit...low imp. injectors have a large flyback voltage. This is what the resister pack absorbs and softens.
It would take out the ecu injector driver circuit...low imp. injectors have a large flyback voltage. This is what the resister pack absorbs and softens.
Gotcha. So the ECU and injectors would have to be replaced?
Use a hand vacuum pump and pull vacuum through the spider and all 4 oil injectors. . . .You can do it through the large line attached to the upper intake as it supplies the spider which in turn goes to all four oil injectors. The oil injectors work as check valve in order to keep air from flowing back and forth between the engine block and upper intake. . . .
You should get 25" hg vacuum and have it hold steady with all 4 oil injectors. . .. . If not, you will have to pull the intake to check them one at a time to see which one is bad.. . . .In my case, I found 3 of the oil injectors would not pass this test and once I changed them the idle improved.
You can also have an EGR valve leak by or leaky diaphragm. You can check the diaphragm with the hand held vacuum pump. Just blank off the EGR and vacuum line and be done with it.
You should check the brake booster with the hand vacuum pump as well. An original one is suspect simply due to its age.
Use a hand vacuum pump and pull vacuum through the spider and all 4 oil injectors. . . .You can do it through the large line attached to the upper intake as it supplies the spider which in turn goes to all four oil injectors. The oil injectors work as check valve in order to keep air from flowing back and forth between the engine block and upper intake. . . .
You should get 25" hg vacuum and have it hold steady with all 4 oil injectors. . .. . If not, you will have to pull the intake to check them one at a time to see which one is bad.. . . .In my case, I found 3 of the oil injectors would not pass this test and once I changed them the idle improved.
You can also have an EGR valve leak by or leaky diaphragm. You can check the diaphragm with the hand held vacuum pump. Just blank off the EGR and vacuum line and be done with it.
You should check the brake booster with the hand vacuum pump as well. An original one is suspect simply due to its age.
EGR and subzero have both been deleted. ACV still intact.
As I said in my last post I believe the issue to be my injectors. I have an 88 car (meaning it came with high imp injectors and no resistor pack). I mistakenly ran low imps in the car with no resistors. From what I've read this will kill the injectors and the ECU.
Gotcha. So the ECU and injectors would have to be replaced?
It's the inductor property of the coil that produces the high back feeding voltage when the field collapses on the injector or any inductor. Normally though if the driver circuit fails it's common that it will power the injector full on.I guess that could overheat and cook the injector if left on for a long period of time but doubtful if anything is damaged on the injector.
So another update here. We're moving in the right direction. Got my set of high impedance injectors cleaned, I rebuilt them and threw them on the car. It started and ran. But it runs terribly.
Idle sits at about 500. AWS is connected. Air bleed screw on top of the throttle body is all the way closed (turned clockwise). If I give it throttle, it'll rev, but it shakes a lot and the exhaust pulses are uneven.
Also forgot to add, lots of smoke from the exhaust. I haven't had a rotary long enough to know whether this amount of smoke is normal, but it seems excessive to me.
It's currently in the 40's where I live, and the smoke is off of a cold start
EGR has been deleted. Everything on ignition side is pretty much new. Coils, plugs, and plug wires.
Fuel system is as follows:
Fuel lab FPRRadium high pressure fuel filter
Everything converted to -6 ANFPR is mounted after the fuel railsStock injectors
Stock ECU
Also what's the main issue of 'running terribly'. Is it running terrible just because the idle is low?
If you're idle is too low, you should open up that Air Bleed/Bypass screw on top of the throttle body. I don't think it should be all the way closed. If it's all the way closed, and idle is HIGH then this points to a vacuum leak. But since your idle is LOW, I would adjust the screw to get the idle to 750 RPM. But you should really adjust the screw only AFTER timing has been verified AND the car has been warmed up/thermowax extended.
Another thing to check, has your idle mixture screw been messed with (screw on Air Flow Meter hidden under a cap)? If the metal cap is gone, it most likely has been touched. This screw can be adjusted to adjust the air/fuel mixture at idle. I prefer not to touch this, FSM even says not necessary, but if it's already been messed with...
Also check the TPS. This can cause a lot of problems if it's not working correctly. It's a quick check as well. Again car needs to be warmed up/thermowax extended.
Also what's the main issue of 'running terribly'. Is it running terrible just because the idle is low?
If you're idle is too low, you should open up that Air Bleed/Bypass screw on top of the throttle body. I don't think it should be all the way closed. If it's all the way closed, and idle is HIGH then this points to a vacuum leak. But since your idle is LOW, I would adjust the screw to get the idle to 750 RPM. But you should really adjust the screw only AFTER timing has been verified AND the car has been warmed up/thermowax extended.
Another thing to check, has your idle mixture screw been messed with (screw on Air Flow Meter hidden under a cap)? If the metal cap is gone, it most likely has been touched. This screw can be adjusted to adjust the air/fuel mixture at idle. I prefer not to touch this, FSM even says not necessary, but if it's already been messed with...
Also check the TPS. This can cause a lot of problems if it's not working correctly. It's a quick check as well. Again car needs to be warmed up/thermowax extended.
By running terribly, I mean:
-the idle is very low on cold start with AWS connected. 500rpm
-when giving it throttle, the rev up isn't smooth. Its choppy, and the car shakes a lot.
When doing all of the work I did to the car, the CAS was never touched. Is it possible for the timing to be off even though it was never adjusted?
The idle mixture screw has not been tampered with. Still has the cap.
TPS was recently replaced and adjusted before when the car was running. If I swapped the ECU, would that affect the TPS reading? From my understanding, it's just a variable resistor, so it wouldn't be affected by the ECU, right?
So, another update here. I've started going through and testing all the components of my intake to see if one may be faulty. I started with the AFM, and tested it per the FSM. Almost everything checked out, except for the last resistance value. The FSM specifies between 50 and 500 with the plate fully open. I'm getting a resistance of 23 ohms. Would this be cause for concern?
If the CAS bolt is torqued down the timing shouldn't really change if you're working under the hood. But checking the CAS/restabbing is a really good check and it's fairly simple too. If the timing is off, I can see it easily causing rough idle/run. Maybe even check the electrical connector of the CAS. You should at least hit it with a timing light. 4A-52 FSM
~~~~~
And woops I mixed up two things... 4A-79 FSM
- Idle Mixture Screw is next to the air box and controls air fuel ratio at idle.
~~~~~~~ 4A-54 FSM
- Air Bypass Adjust Screw. This is part of the AFM housing. This screw lets air bypass the air flow meter (kind of like vac leak since it's air not being measured).This is what I was referring to having a metal cap. My car previously had an AFM that had a metal cap removed and screw clearly adjusted. I found another AFM with the cap still in place (factory setting) and it helped some of my idle woes. Another thing to check.
The AFM low resistance value, I'm not too sure if it would cause issue. I would think the 0-infinity check is more critical? But again not too sure.
TPS Adjustment after ECU swap.
Yeah swapping the ECU shouldn't change. Only thing I can think is if the contacts at the ECU are corroded then it might read slightly different because of resistance at the contacts. But again, this is a fairly simple check, and if not correct can cause issues.
So a bit of good news here. Just wanted to update the thread for anyone who's helped and/or has been reading along. The car runs now. I didn't do much between last time and this time, but whatever I did fixed my issue. Here's a list of what was done. If anyone thinks one of these was the smoking gun, I would love to know:
-adjusted TPS cold. Closed was 1.2kohms, WOT was 4.8kohms
-topped off the coolant at the stat housing. Radiator was full, but stat housing was bone dry. Car wasn't ran long enough for the stat to open.
-deleted the EGR solenoid and capped the associated vac lines
-tested resistance of the CAS. Was within spec
-tested voltage at atmosphere pressure sensor. Passed
-inspected FPR for possible failure (even though it's brand new). Passed.
-tested resistance across pins on the BAC. Passed
-Disconnected the AWS. Was never a fan of it anyway, and figured it may cause issues when trying to diag the issue.
-put some fresh gas with a healthy amount of premix. The car had been sitting for about 4 months and I figured whatever was in the tank may have started to go bad.
Among all of that, something caused my car to suddenly start working. Here is a video of the idle:
If you listen closely to the idle, you can hear it skip for a second, then smooth out. Then it'll stumble again for a split second, then smooth out. What could be causing this?? Appreciate everyone's help
I just went through the same thing and managed to smooth mine out. .. Maybe some of my experience can help.
I just did the EGR blank, TPS set, BAC replacement, and oil injector change out.. . . along with other parts.
The EGR can leak through the plunger seal and not just the diaphragm seal. . . .I concur that the EGR should be blanked.
Also check that the dashpot vac line goes to the correct thermowax valve port.. . .Or just cap/blank it off at the block port if it not removed already.
Idle sounds high too . . . Was the car up to temp?
I just went through the same thing and managed to smooth mine out. .. Maybe some of my experience can help.
I just did the EGR blank, TPS set, BAC replacement, and oil injector change out.. . . along with other parts.
The EGR can leak through the plunger seal and not just the diaphragm seal. . . .I concur that the EGR should be blanked.
Also check that the dashpot vac line goes to the correct thermowax valve port.. . .Or just cap/blank it off at the block port if it not removed already.
Idle sounds high too . . . Was the car up to temp?
EGR and the associated solenoid have both been deleted. I've retained the ACV and it's associated solenoids, as well as the FPR vaccum solenoid.
Do you mean the dashpot, or the double throttle actuator? If you mean the dashpot, there is no vaccum line that goes to it. If you mean the double throttle actuator, I had disconnected the vaccum line going to it with the car at idle, and there was no change in idle quality. Perhaps it's not functioning?
As for the high idle, the car was not up to temp. It was about 2-3 minutes off of a cold start. I didn't let it get up to temp as I have yet to bleed the coolant system. I just wanted to see if it would run and hold idle smoothly.
Was that your first time disconnect the AWS? Did you remove it completely or just disconnect the electrical connector? Possibly the solenoid/valve wasn't closing all the way or hose has some leak? Maybe don't worry about it too much since it's running better now lol.
That is probably my favorite OEM color for S4. I love the contrast with the black trim. Your paint looks like it's in fairly good condition too.
Was that your first time disconnect the AWS? Did you remove it completely or just disconnect the electrical connector? Possibly the solenoid/valve wasn't closing all the way or hose has some leak? Maybe don't worry about it too much since it's running better now lol.
That is probably my favorite OEM color for S4. I love the contrast with the black trim. Your paint looks like it's in fairly good condition too.
Thanks!
No I've had the AWS disconnected before, and my car always ran better without it. I just unplugged the electrical connector at the radiator. Is there a way to disable it entirely??
Lol you should see the paint in person. It's not so clean. But I agree. The silver with the blue interior has always been my favorite combo
No I've had the AWS disconnected before, and my car always ran better without it. I just unplugged the electrical connector at the radiator. Is there a way to disable it entirely??
Lol you should see the paint in person. It's not so clean. But I agree. The silver with the blue interior has always been my favorite combo
Hahaha I see. To disable the AWS you can just remove it entirely by unplugging the elec connecter and removing (2?) bolts. But you have to cap off the spots where the hoses were connected. One on the intake/dynamic chamber and one at the split air pipe. So if you remove it you'll have somewhat large vacuum caps and a disconnected connector (harness side), if that matters to you. From what I've read it does not affect anything else by disconnecting. Just stops the 3k hold at cold start up.
The way you have it now. If you have leaks at the hoses of the AWS or if the solenoid is not fully closed you'll have a leak. But if you don't have any leaks and solenoid is closing properly (you can verify by trying to blow air); functionally I believe it will pretty much be the same as described above.
Just wanted to update here, for anyone following along, or who has helped out along the process. Thank you guys.
I took her out for a drive today and she goes. Shifts fine, reva fine, all is good.
The only issue I'm coming across is the idle. It is high. Even with the car fully warmed up, at OT, the idle hovers around 1200. Does this sound like a thermowax issue? TPS is set correctly, and the air bleed screw is all the way closed.
10-26-21, 05:01 PM
