Haralambos

Hey guys, so I just finished my first rebuild and I'm having some issues. I guess the good thing is that I can start the car. So here's whats going on. The car will only start if I prime the housings with oil. I expected this since it is a fresh build but after an hour of idling and me reving the engine every once in a while I figured it would start up or at least give me some combustion. Problem 2, I am idling at 1.6K to 1.9K and it seems to rev cyclically. I'm not sure whats going on with this, the BAC screw doesn't seem to change anything. The only thing I can think of is the TPS needs to be reset after the engine warms up. When checking the timing, the dots at the above mentioned idle are at the 3 o'clock position. When i rev the engine the move 180 to the 9 o'clock position. Rotating the CAS doesn't really change this very much. The only thing I can think of is that maybe when I was trying to set TDC I didn't. Tips on setting TDC would be appreciated. Past these issues the car seems to be ok, it was still smoking after running in the driveway for about an hour, but it wasn't too bad. Anyway, some help would be appreciated. I've been dying to drive my car since I started the project back in May. I will try to figure out how to get a video of the idle up.

Here are some specs on the car.
87 Turbo, that had an N/A put into it. I purchased a JDM and rebuilt it and is obviously in the car now. BNR Stage II, RB Rev II exhaust, removed ACV but I left the rats nest on and plugged all the lines I didn't need. One interesting thing is that when the fuel lines are set up as they should be on a JDM (opposite the US cars) I get no fuel to the injectors. When i switch the lines i get fuel. I'm not sure what that's all about. Anyway, I'm open to suggestions. Thanks!

dwb87

iTrader: (22)

There is a screw to adjust the idle on the TB, near the throttle assembly, under the stock intercooler. Set your TPS for sure.


I found a thread that explained how to set your timing this way:

"Just set the timing manually, I had a timing issue, set it with a light and it was still way off ( Definitely my fault) but I found it you set it this way it is much easier and accurate.

There is a little yellow mark on the Eshaft pulley closest to the front cover. Line this mark up with the little pin on the front cover above the pulleys.

Take out the CAS and line up the marks on the gear and housing.

In order to keep the marks lined up when you re install the CAS take off the top cover (two screws) and hold the gear with your fingers so it doesnt move around when you install it.

Bam, timing is set"

Do you have a FCD or an aftermarket ECU?? Have you ported your wastegate? (Aaron Cake's Extreme S4 Wastegate Porting)<-link

Haralambos

Yea I'm definitely going to adjust the TPS for the high idle issue.
I found that thread on the timing right after i posted. Hopefully when I get out of work today i will be able to try it out.

I do have an FCD to hold me over until i get an RTEk and the BNR turbo has a massively ported wastegate.

One other thing is that the BAC is sucking in air from atmosphere. I couldn't find a way to hook it up to the charge pipe. Hopefully i will figure that out soon too.

Haralambos

So, I tried re-timing the engine by aligning the drilled out spot on the front housing pulley and then attaching the main pulley. Same result, dots align to about 3 o'clock. I am using the main pulley off of an S4 NA, don't know if the alignment would be off due to that.

Anyway, I didn't have time to actually properly adjust the TPS but i did play with the idle screw. I can get it to idle at around 1.5k with a surge of 200rpm. I took a video of the surging at 2k before i tried adjusting the TPS. http://www.youtube.com/watch?v=-Xh3a...&feature=email I did take the throttle body apart when I rebuilt the engine. Maybe i put the TB back together again with something off by a little.

Past that, I can drive the car and it drives fine a long as you don't try to stay at one set RPM, it will surge when you do that. No problems on acceleration and deceleration. You think that is due to the engine still needing to wear in.

I still need to add oil to the housings to get it to start. I'm hoping that after a couple long drives, the seals will wear in and allow the car to start without the oil trick.

Any thoughts?

RotaryEvolution

iTrader: (30)

take off the intercooler and find the screw facing up with the spring under it at the rear top center of the throttle body, jam that screw down as far as it can go and reinstall the intercooler.

bumpstart

besides needing the tps cal,that s4 na pulley is not helping, get a turbo s5 unit and i think you may find differences
there was another thread with perhaps this result in the last month

AGreen

iTrader: (11)

After my rebuild, I had a few issues as well. First, it would flood when warm. Turned out the wires had come loose from the connector going to the water thermosensor connector. So it was plugged in, but the wires didn't make contact and required a de-flood every time I started it warm. Cold starts were ok.

I installed the CAS drive gear backwards. I could never get the timing right, but after a lot of thought, I pulled the front cover and found the drive gear backwards, things made sense.

The TPS won't cause the high idle, but it does cause surging. Make sure the throttle body is closing all the way (that's the screw that dwb87 was talking about)

If you have any vacuum leaks, that will cause a high idle as well.

And you can't really properly set the timing until you get the idle, well... at idle. Around 750 rpm.

RotaryEvolution

iTrader: (30)

actually, don't mess with that idle screw unless it is a last resort. that screw can only cause the idle to lower, not rise like this person is describing which to me points to a sticky thermowax.

and definitely put the original pulley back onto the motor. why on earth would you swap the pulley? timing is critical to a turbo motor, now having the USDM n/a pulley the marks are going to be off.

AGreen

iTrader: (11)

I was talking about the throttle stop screw.

RotaryEvolution

iTrader: (30)

i referred to that. i just don't want people messing with the throttle stop screw as a first measure, it's a last resort on the list after all other diagnostics fail.

in this case the throttle stop screw probably won't do a thing anyways, except he will lose it's original position. that is unless while screwing with his throttle body that he adjusted it down and didn't set it back to spec properly.

it's just that lately i have seen tons of sticky thermowax elements which have been jacking up people's idles.

Haralambos

Is there somewhere that defines stock locations of screws(etc.) on th TB? I took it 100% apart to fix a bent shaft.

AGreen

iTrader: (11)

Was this before or after the rebuild?

Haralambos

Before. I got the jdm engine and started taking it apart and noticed the severely bent shaft. So I took it apart, with lots of pictures, fixed the shaft and reassembled. Everything looks to work right but I don't know how to adjust everything.

bumpstart

go to http://foxed.ca/index.php?page=rx7manual
on there is the s4 turbo training manual
( i uploaded it and this is where it ended up )
and you shall find it has all the TB setup angles in it

Haralambos

Thanks for all the info guys. So I adjusted the TPS to 1Kohm (cold engine) and cranked the thermowax screw all the way down (cold engine). I start the car with a small amount of oil in the chambers, starts up and idles at around 1.5K. Sounds much better than the video posted before. Much less surging. As the engine heats up RMPs go up, obviously. So i shut down and adjust the TPS again and the start the engine without oil. It needed a little gas but started. Idles again at 1.5K. So I decide to adjust the BAC to lower the RPMs and it seems to do nothing. So i adjusted the idle screw and it brought it down a little. I don't really want to play with that screw too much. What does the screw under the idle screw do? Do i need to adjust the variable resistor? The only other thing that could be keeping the idle so high is that the butterfly flap is open out of spec. Would that cause the high idle? Thats adjusted by bending the stop tab right? Check out the videos:
http://www.youtube.com/watch?v=zdq9QcAaTJI
http://www.youtube.com/watch?v=CBVyqEtXYZY

In all it's running smoother. Just need to figure out the high idle.

I assume that the smoke will go away with time, there's probably a lot of oil in the exhaust.

As for timing, i am looking for the s4 turbo pulley. The one that came with the engine is garbage. Thats why i put the NA pulley on.

Let me know what you guys think. Thanks for the help.

RotaryEvolution

iTrader: (30)

make sure there's slack in the cable, if not then try the idle screw again, i wasn't aware you messed with the settings.

Haralambos

So I got the car to idle smoothly at1200 rpm by playing with the idle screw and throttle cable. I'm content with that for now until I break the engine in. The bac is turned all the way in and raises the idle a little as I turn it out. I still assume the tb isn't set up 100% since I can't get it to idle any lower.

As for timing, I called mazdatrix for a new pulley and they told me that accessor pulley (with timing marks) comes pared with the eccentric shaft hub. I'm not sure I believe that. Any one know the truth about that.

RotaryEvolution

iTrader: (30)

they are a paired set. on the USDM market cars there is 2 different hubs and pulleys, mixing them can result in a brick, especially in turbo applications.

boostkeepsmesane7

iTrader: (1)

How did u go about fixing your water thermo sensor problem I think I have the same problem

AGreen

iTrader: (11)

Chopped the connector and bought a new bosch EV1. I think the tab had to get filed off the thermosensor for it to fit. I can't remember.

http://www.diyautotune.com/catalog/f...-ev1-p-48.html

beefhole

iTrader: (29)

"As for timing, I called mazdatrix for a new pulley and they told me that accessor pulley (with timing marks) comes pared with the eccentric shaft hub. I'm not sure I believe that. Any one know the truth about that. "

This is true. That ONE pulley with marks is made for that specific hub. It was stupid that mazda did this, but that's life. As mentioned, you should ONLY use the pulley that's on the motor you have and no other.
I made this mistake when I was disassembling 2 motors at the same time. I didn't mark what pulley came off what engine, and then when I rebuilt the one good motor, I was in the dark about my timing.

For piece of mind, I splurged and bought the racing beat main pulley. This will always indicate the right timing as it is a one piece, keyed pulley. So I put it on, set my timing using it, then put the stocker back on and remarked it. I was off by 2-3 degrees with the wrong pulley!

Haralambos

So for the timing, the pulley that came with the engine is garbage. It's rusted and i can't find the timing marks. It sounds like my cheaper option is to go with the mazdatrix pulley solution. My question though is, can I remove the pulley while the engine is still in the car? I would hope/assume that the distributor drive gear and oil pump sprocket would stay in place no problem. Also, i could just put the car in gear to hold back the engine from turning when i remove the eccentric shaft bolt, its only 90ft-lbs. Let me know.

AGreen

iTrader: (11)

hold the clutch in, breaker bar on the front bolt, blip the starter. That should break it loose. Now, the key is to KEEP THE CLUTCH PUSHED IN the whole time. Keep the clutch pedal depressed until you've torqued the pulley bolt back down. This will keep the stack from dropping.

Haralambos

I'm back again guys. So, i replaced the timing pulley and got the car timed perfectly. So i drove the car about 200miles so far and ran into a problem. Literally, once i hit 200miles i lost all engine power. I can start the car and it idles no problem. With no load on the engine, i can rev it (only went to 5K, I don't really want to rev it any more than that). Once i put it in gear and try to drive it it has no power, i can get it moving but as if it has a 50hp eninge in it. So i checked the obvious, TPS is OK, MAF is OK, i have a spark on all plugs. I don't think it's a fuel issue since i can rev it with no hesitations when the engine has no load. I'm not sure how i would even check if it was a fuel issue. The only thing i can think of is a vacuum leak when the engine is torqued when trying to move. I need to get out there with a propane source to sniff that out too. Do you guys have any other ideas as to what might be wrong. I'm at a loss at the moment and not sure how else to trouble shoot. Thanks in advance.

dwb87

iTrader: (22)

Have you been taking it easy on the engine thus far? (Breaking it in properly.)