Alright... here goes.

I have an 88 TII with the 3" exhaust all the way back, HKS PFC F-CON, HKS FCD, HKS Intake, no emissions. I have done everything in the book to this thing and it still wont run right.
I finally got the thing to start everytime you turn the engine over. And I solved the idle problem. Now comes the hard part... I take the RX out and there is big time hesitation during acceleration. It last throughout the whole rpm range. It also hesitates and backfires when the car is stationary and I jam the gas. But if I'm gentle on the gas... its fine.
So far I have checked every piece of equipment on the car short of the fuel pump. I have checked, and rechecked the timing at least a dozen times. The marks dont match up when the car idles either. I tried to reset them as the book states, but no sucess. She sounds strong on idle and I dont hear any pops, or knocks, or pings. I've had the engine compression tested about three months ago when it wouldn't run at all... its good. Ive changed the leading coil, O2 sensor, secondary injectors(I found out the other ones were too big... like 520cc), and three sets of spark plugs.
The HKS FCD is set on 2, the PFC F-CON has a little dial on the inside of it, and that is set on 3. The wiring harness for it is a little old and ratty, but it works good. the battery is grounded right to the engine block, and every bolt is tight.
I have absolutely no idea where this problem exists or what it is. If there is anybody out there that has had a similar problem or knows that key to unlock this problem so I can get my baby back out on the road where she belongs; I would appreciate any help you could have.

 

first thing is to unplug the f-con and by pass it. just don't drive to hard or you will risk running lean. but then you can tell if it's running ok.

what do you mean by the timming not lining up? maybe you should try and fix that.

I wouldn't be surprised if it was the fuel pump. you should have a bigger one anyways.

can you find out what secondary injectors you had and what you put in?? stock is 550, but having bigger would be a good thing with your mods.

also I would do another compression test.

 

I'm like Scott...I don't understand the timing problem. You say the marks do not line up. What happens when you loosen the cas and rotate the cas to line them up?Is your problem that the cas won't rotate far enough for the lines to line up? Maybe hitting the travel stops of the cas prior to the marks aligning? Inch wise, how far off is the lead mark from aligning with the pointer? Sort of a clue.

 

Scott,
I cant unplug the F-CON and run the car. Every single vaccum system has been removed save the turbo system vac lines. I put stock injectors back in the car... I had 850cc in there before. I have to wait to do another comp test. What I dont understand is that with all the afterburn and the bogging during acceleration... wouldnt it be getting too much gas? And for HAIL... The car doesnt want to idle at the prescribed 725-750 rpms. It will die if it is set that low. It idles fine at around 1500 rpms. Thats what I have it set to. I understand that it should be slightly advanced for that setting. I'd have to say that the marks were about an inch apart. Although the closer I get the marks to line up... the crappier it runs. Now when I loosen the cas and turn it clockwise(retard I think) it runs better. It really is a screwy car. It all started happening around May of this year. The person I had to take my car out and run it for me, said that all of it started out gradually and not all of a sudden. So I hope I can rule out some catastrophic failure of any engine internals. Like I said I had it comp tested 3 months ago and it checked out. I will do another test. Its not like I can take it to a rotary shop nearby. Im in Illinois and there isnt a competent shop anywhere that I have seen. I have an APEXI timer w/ air-fuel ratio monitor on the way. was thinking of getting the APEX S-AFC to replace the HKS unit. Also, where I have the F-CON located( in the glovebox ), it runs better sticking out than stowed in the box sideways. It may be due to the harness. but I moved it to the floorboard and it seems to be doing better. Do either of you know what setting this F-CON should be set on? Inside there is a little dial 0-9, and three sliding red switches. What should these switchs be set on?

 

Also I found out that the turbo solenoid was disconnected from the manifold. I fixed it already. Would that being disconnected have anything to do with the performance issue? If it was being run without the turbo activated... how could I rule this out as a cause? It is hooked up now, but could this... over a period of time caused something to fail... or give the computer mixed up messages on the amount of fuel to use?

 

I don't think you can check the timming at 1500 rpm.... that's probably why that's way off, don't worry about that untill you can get a lower idle. if it won't idle below 1500 and doesn't have any power I'd say the motor might be gone. by turbo solenoid do you mean the wastegate line?? if that is off it will cause your boost to sky rocket. which would lead to a blow eingine... I say next step is to compression test.

have you checked for any vacum or intake leaks?

 

but first unplug the f-con. you can unplug it. if the car runs with it it'll run without it. it only intercepts the signal to the ecu and changes the fueling a bit.

lift up the carpet to the ecu. the f-con harness should just be pluged inbetween the ecu and stock harness, just remove it and plug the stock harness into the ecu and bypass the f-con. they have been know to die. and by the fact that the car changes the running condition by moving the placement of the f-con... that might be the problem.

do you sill have the stock boost sensor on the shock tower? you should even with the f-con.

as for the switches you have to phone up hks and tell them your mods and they will give you the correct setting. but I think the car should still be running alot better even on the wrong settings.

 

Scott,
I'll try and unplug the F-CON tonight... although I will have to wait to do the comp test tomorrow... need to go and get the tester. I replaced all of the vaccum lines that have anything to do with the outside peripherals. And I checked the vac spider when I changed the injectors... got and extra one just in case that is bad. I will let you know the results of both tomorrow. Gotta go to work on this beast again. Wish me luck!

 

also check for leaks between the turbo and air flow meter. the TID.

 

i fixed a 88tII once that had the same problem and the tps was the culprit.car still runs fine to this day.

93fd 13.5@101mph

87tII soon to be racing

 

I unplugged the F-CON but it wouldn't start. What is the TID? Can I get the TPS off of an N/A RX and replace mine with it?

 

after you unpluged the f-con did you plug the harness back into the stock ecu??...

did you plug it back in and start it? does it still start now after?

 

yeah... I plugged the ECU back in. It wouldnt start. And I know its flooding. Stinks of unburned fuel. think it could be the TPS like rotary said? It does this often.

 

dude, its the TPS............just get a new or used one and you'll be fine

i had the same problem on my 91 T2. checked the codes...and both ranges of the TPS were shot. slapped in a new one. poof! runs PERFECT again

 

Erik-

What source did you use to get the codes for the TPS??


J

 

i have a copy of the 89-91 factory shop manual and the codes are listed in there. on the 87-88's i'm not sure if you check teh codes the same way...but i know there is a way to do it. i think scott89T2 has a listing of codes on his site...and i think at www.luvinmyrx7.com or some site like that has a downloadable copy of the 88 shop manual. good luck dude

 

I changed the TPS, replaced injector seals, and put the old larger injectors in (720cc) and set the computer back to its original setting. Car still won't start and in fact another problem has arisen. Gas is leaking from out of the exhaust pipes!!!

 

probably flooded now. do a search to find out how to unflood. basicly pull fuses out so the fuel pump doesn't get power then you crank a few times to get the gas out of the engine. you might need some new spark plugs now too.

 

If the tps is in fact bad would it trip any sort of code in the ECU or do just have to use the good ole mulit-meter and test it out??

J

 

Sounds like you have a problem in your ignition system if it is flooding that bad. Could be fouled plugs, bad coil(s), or something similar. I know you said you replaced one of the coils, but what about the other one. You also might check your plug wires as well. Maybe you should get some 10mm plug wires. Good luck,

Derek

 

I unplugged the fuel pump and crancked it a few times. Battery started to die out. I have to get a new one anyway. I'll have to wait til tonight to go get a new one. I checked the new TPS with a multi-meter. Both ranges checked out by the manufacturers manual. I checked all three coils and they are good. doesnt tell you how to check the igniters, but every time it has flooded in the past... the leading plugs were wet and the trailing plugs were dry. Same thing here. Wiped them off. and I already have 10mm wires. Like I said, by the time I track this moving gremlin down I'll end up replacing the whole engine bay. Maybe that wouldnt be such a bad idea if there was a rotary shop close enough.