MacLoGoS

Hello,
So i have a 1985 GSL-SE with a S5 turbo swap running Rtek 1.8 with 680cc primaries and 720cc secondaries. Stock fuel pump ran to constant 12v source with switch. So far everything has been replaced brand new or has come out of a car that has been running perfect with the parts in it. The prob im having is when i rev the car past 3k rpm's it sputters and acts like its misfiring. I got it to rev smooth to 3k by pulling off the brake booster vac line. Still runs super rich even with that vac leak to lean it out. Changed the O2 sensor, coolant temp sensor, new injector grommets, fuel pump, boost sensor. Last thing i didnt change was the ignition coils. Everything else has been changed. The mods are FMIC, stock S5 turbo with ported wastegate, and HKS blowoff valve. If i reconnect the broke booster andseal up the vacuum leaks the car runs like crap and the A/F guage wideband shows the car running in the low 9's when it should be at 14. Really weird. The engine is freshly rebuilt and only has about 1000 miles on it. I have checked the compression and its perfect 110 front and back. I have also replaced the tps and still nothing. Also changed the ecu to another rtek that was in a perfetc running car and still nothing. I also have SAFC 2 but trying to lean it out doesnt seem to help much at all. I just want to know how to fix the sputter/misfire noise i hear. I have spent a **** ton of money on the car and have never gotten to drive it once without it running like crap. Please help me out if you know how to possibly fix this issue. Hailers or Satch please help if you think you know what it could be.

walken

iTrader: (6)

s4 or s5 electronics?

MacLoGoS

It has S4 electronics. I just swapped the trailing coil and it seemed to help a little bit so now it can hold idle with the brake booster reconnected. Gonna try to tune it on sunday but still any clues on why it would run like that? Oh and it also has S4 intake manifolds upper and lower. Front mount intercooler with greddy throttle body adaptor.

lastphaseofthis

iTrader: (8)

This is your problem area. does seem like maybe the A/F scale is inverted? Tried to re calibrate it? can you force the sensor rich with butane?



You could back probe the injectors' OHMs at the ecu, to make sure you have 10-16 Ωs.
you may have a bad combo of injectors/wiring harness.

what AFM are you running? I would have an s5 turbo, or a 20b one.



I run my 85 GSL s5 n/a swap on just the stock 680cc injectors and stock 85 AFM/ECU, it runs great all the way to 6k, then leans out.. so i shift at 5.5k ... it barks 3rd. (and has so much more in it.)

MacLoGoS

Currently running S4 turbo AFM with all S4 electronics. All sensors are S4 turbo. The ECU is a S4 turbo ecu with rtek 1.8 The injectors are fine. I have tested them and they also came from a running car that i have seen run perfect with the same equipment. So i know its not the injectors for a fact. Now the car seems to run much better but like i said i will have to wait til sunday to see if i can tune it out. I had unplugged the trailing coil and it ran the same. So i changed out the trailing coil and it leaned out alot more and the idle is holding much better. I will let you know what happens after i mess with it on sunday. The AFR has been calibrated correctly and it was also used in the same running car that i seen run perfect. So its hard to believe the part would just switch but i will double check. Thanks for the info.

MacLoGoS

OK update time!!! So i swapped both the leading and trailing coils and now the car idles like a champ and runs really smooth until i hit boost. As soon as i hit boost it stutters and hesitates like a mo fo. So i used the SAFC2 to lean out the injectors and with it leaned all the way out with 50% corrections the car still runs so rich in boost that it causes stutters and the AFR reads 7-10 (this is way too rich and setting my safc that lean should have possibly killed the engine from to little fuel.) So now when i turned the resistor to rich setting the engine just died. Is there anything im missing here that would cause the engine to run that rich? Im using a stock fuel pump with stock fpr and 680cc primaries and 720cc secondaries. When im cruising and not hitting boost the afr reads 14.8 when in closed loop so i know thats running good. But boosting is the pain in the *** now. Any advice is much appreciated.

FelixIsGod29X

iTrader: (50)

Isnt it true that any injectors besides stock will override the fpr?

beefhole

iTrader: (29)

No. The fuel pump (upgraded) would do it. An larger injector dumping more fuel at the same pulse if anything would lower the pressure as it is letting in more at the stock pressure.

FelixIsGod29X

iTrader: (50)

O Duh i was thinking about it all wrong and i knew about it before -_-

MacLoGoS

Bump... Anyone know why a car would run super rich with stock pump? All new sensors and good TPS? Rtek 1.8 and SAFC2 but still runs super rich. Please help!!! Car has S5 turbo block with S4 turbo electronics.

RXSpeed16

iTrader: (41)

Sounds like a boost leak. Can you verify your boost pressure? Have you tested your intake system for boost leaks by pressurizing it? Or maybe the BOV.

The mixture resistor won't affect anything other than idle afr's, so no need to bother with it if your problem is only under boost.

MacLoGoS

How do i check for boost leaks? I sprayed starter fluid all around the engine and i have no intake leaks at all.

misterstyx69

iTrader: (142)

you are only checking for vacuum leaks when you spray.
to check for Boost leaks you have to Pressurize the intake.
Make up a cap that will fit the mouth of the turbo and attach it with clamp.
put a tire valve on the cap so you can inject air from an air hose into the system.
put air to valve(about 10 psi) and listen for leaks.

MacLoGoS

OK so turned out it was a loose wire on the ecu plug that was causing the boost issues. Thats all good now since it boosts all the way thru gear no prob. But the light throttle hesitations have returned and the car wont hold idle. I have to bump it up to 1500 rpm for the idle to hold and the engine shakes so bad i cant even drive the car safely. I relocated the battery to the rear passenger side bin. Could a bad ground cause issues with idle and light throttle hesitations? Im talking about the main ground to the battery. All other grounding for the harness and ecu are done correctly and are clean. I removed the SAFC 2 because when it was connected i could get the car to hold solid idle but wouldn't let me boost. Removing it lets me boost but the car cant hold correct idle and shakes. Thanks for any feedback on this. Also i have the BAC valve on the car but when i turn the screw it does nothing. I think its ok cause when i plug it into the harness and turn the power on it clicks and i hear it working. Another question about that is since im running a front mount intercooler setup i was not able to connect the vacuum line for the bac to anything. Would that cause issues with BAC adjustment? Should i just get a block off plate for it and tune the idle?

RXSpeed16

iTrader: (41)

The BAC is supposed to draw metered air, so having it disconnected from the intake piping is going to act like a vacuum leak and screw with you idle.

Either plumb the BAC feed tube into your intake tubing (recommended) or block off the BAC and adjust the idle speed via the throttle body screw.

MacLoGoS

Thanks for that info. I had always wondered about that. I have a block off plate for the BAC so i will pop that on and try to adjust the idle. Do you think that the intake leak from the BAC would also be the cause to the light throttle hesitations? Im gonna reground the battery and see if that helps too while im at it. I will repost again when i get some results.