1G 3 1990 AWD problems can't figure out

[biglady112]

Well we finally got this car off the ground. All was well on the start up. Then once it reached operating temperature it started surging and idling high. Got the TPS and idle stop adjusted and it helped a little. A few things we think it might be is a vacuum leak/boost leak. All emissions stuff was removed, EGR block off and most vacuum line eliminated. Store was closed so we couldn't fix the broken boost leak tester. Bad ground on the IPS switch. Stuck throttle. We got the throttle to stop sticking finally.

Second is the tach stopped working. Not sure when as we got the car started the other night but was waiting on new injectors and took it back down and put thing back together. We swapped tachs, coil packs, CAS, ECUs and finally the power transistor. Oh, and swapped gauge clusters.

The transistor actually died today. That was one of the first thing we fixed. But, upon removal the connector we had 2 wires literally fall out of the back of the connector. Couldn't repair it, so I cut the one off my mirage in hopes to wire it in. Worked great but car would not start. Then we swapped in my transistor and she started again. Swapped coils and car ran the same so good there.

I am getting 4+ volts to pin 109 on the ECU. I believe this is the input. Can't get any reading on the dash harness from any pin with the car running or not, not sure what the deal is there. Same with most of the pins on the ECU as well. Never seen it like that before. ECU/DSMLink are registering a tach signal though.

Third, right around the time the wires fell/broke out of the connector it started to idle with a miss. Give it some gas and it doesn't sound like it is missing. If it idles lower by chance it doesn't sound like it is either. The #3 injector plug pretty much broke its wires upon removal as well. All 8 wires to the injectors are in extremely bad shape. At least half are gonna break looking at them. The others are not far behind.

I did a temp solder job last night until we can get new connectors to solder in. It works fine and the car responds to it being unplugged. Even under wide open throttle it runs great. But it just idles with a slight miss now for no reason. As I said, this happened about the same time the transistor connector broke.

The car doesn't really get any better or any worse no matter how I set the 1600's. It was rock solid when we first started it, then after about 15 minutes of idleing this crap started for no reason. Timing and fuel have been zeroed out to eliminate the other tune. Airflow sliders as well, now that the timing belt has been done correctly. It runs like a raped ape on the 14b wastegate and everything zeroed out.

I was trying everything to see what was and wasn't working. Launched it just to try out and the car almost came around on itself and hit a fellow dsmers car next to me in the street. So WOT does not seem to act funny, yet. The way the car is is going to be impossible to tune drivability.

So there it is, tach doesn't work, crazy idle surge/high idle and car idles with a slight misfire. Car is running on E85 as well. New fuel filter- 0 miles, new battery, new 14b, new FMIC, Tial BOV (7lb spring), DSMLink, PLX wideband, Ford 1600's, Walbro 255hp, Hallman MBC, New radiator- 0 miles, fresh timing job (verified at least 100 times), act 2900, aeromotive regulator, GM-MAFT set correctly (zeroed out), base timing set with ECU grounded, and who knows what else.

Any ideas? Losing patience. Want to tune. I won't let it leave the driveway until these three things are resolved. FACK.

Also forgot to add that a catch can was just installed. It is using a hollowed out PCV. Both valve cover vents running to the can just like we had it on my Mirage.

And when the IPS is plugged in is when it surges really bad, when it is unplugged it idles really high and that is when we hear/feel the misfire. When unplugged it does not surge.

Steven

 

[Below Ambient]

1600's are too big for link, e-85, and a 14b.. tuning for e-85 would be approx 1.35 parts for every 1 part of regular gasoline...

my experience with DSM link is that the most injector you can run is 850-950cc, although that was about a year ago and you could have different firmware...

id think with a 14b, link, and e-85, 850-950cc would be the better choice...

as for the tach ill bet the archives have some answers... i have a 90 and never had any tach problems thus far...

GL

 

[biglady112]

Well you are 100% wrong. I have at least 5 other cars here with 1600's including my own that run 1600's without a hitch with DSMLink. Just because you don't know how to tune or know how to set up a car doesn't mean the rest of us don't. And the owner is preparing for more than the 14b. Way to think of that one.

The problems we are facing are not tuning related. I have had two 90's and an 89. So I think I have the mechanical covered. These problems are electrical as we spent all day swapping parts to no avail.

Anyone else have decent input? As I have spent 6 straight days now working on this car and can't barely think now.

Steven

 

[Below Ambient]

just lending my experience... no reason for you to get all over my ass about it... gl with your thread

 

[biglady112]

Both ECU's used are in fact 1990's, or at least according to CAPS. They are early 89 to early 90. But, no less than 7 days ago did the tach work. We were tuning the car and calling out rpms while dialing in the MAF. FIAV is still intact. Throttle body was recently rebuilt by Hal Landry.

There are definitely some wiring issues to figure out now. The car actually idles great until it warms up and things go wrong. The ISC seems to be working correctly according to DSMLink, coolant temperature seems to work proper as well. TPS is now a known good one and set and working right.

ZERO boost leaks. Also swapped in 2 different ignition resistors (silver plug with white wires coming out of it). No luck there.

The car is idling rich. Around 11:1 right now. Can be tuned out but this surging is pretty much making it impossible. My Mirage started off the same way and some miles made it all better. This could be my slight misfire, but it only misfires while surging. Air/Fuel is monitored by A PLX M300 (new). Tach adapter appears to be there on both coil packs.

I will post a log next week when I get back from vacation. I am escaping the world for a week. I may just try a short term solution and try wiring in the tach like an aftermarket tach to see if it responds. Probably won't run the car this way, but we will see.

Thanks for looking and any help/advice. Have put in at least 40 hours on this car this week plus the 45 at work.

Steven

 

[Below Ambient]

try swapping out the ISC... sometimes they go bad by acting up when the engine reaches operating temp....