Hey guys, I've got a 90 GXL with a recently rebuilt/ported motor, ported intake mani's, 2.5 midpipe and corksport SS catback, and a few problems.

1) When I get between 7 and 8k rpm, it stutters and hesitates sometimes...is this more likely to be an ignition problem or a fuel problem or a littlle of both?

2) I get a random "Add coolant light". I've gotten the light 4 or 5 times, and each time immediately stopped, let it cool (to where I could open the rad cap), checked the coolant levels, and tried to see if I could fit just a little more coolant into it, but this hasn't helped. The light goes off if I take it out of gear, wiggle the shifter, and put it back in gear. It also only does it in 2nd gear, usaully between 2.5k and 3.5k. It can, it seems, hold just a little more coolant each time I do this...


3) Lastly, I'm having a bit of an idle problem. I've checked the TPS (and replaced it cause it was out of spec), checked the coolant temp sensor (in case it was corroded and was it forcing it to run rich), checked the BAC (got proper resistence levels on the BAC itself, but got weird readings when I tried voltage-checking the lead from the ECU). Could it be that that transistor is gone on my ECU...would it be easier to replace the ECU or the transistor if so?

As I was writing this, I thought "hmm...maybe the ECU could just be bad, and causing the whole mess of things..." Could that be the case/has anyone heard of a problem like that? Anyway, thanks for taking the time to read this, and any help at all is appreciated...this is stuff is driving me nuts...
-Matt

 

What kind of idle issue do you have? Stall at stoplights with a load? Bounce? The add coolant buzzer could be a small leak from somewhere that you aren't noticing. The sputtering/hesitationg I'm not to sure about, but have your coolant system pressure tested and see if you can find a leak, and explain more on the idle issue.

 

Idle issue: stalls under a/c load...sometimes...other times it just drops and starts bouncing very low (a/c, by the way, has a leak somewhere...need to do something bout that..), bounces a little most of the time, but it seems to even out on hot days.

 

sounds like your BAC is stuck closed (or open), clean it! goto http://www.1300cc.com and click the enter button, then under tech or how-to read the article on cleaning the BAC, that should fix your load issue (a/c etc) Then have the coolant pressure tested, and go from there

 

About the turbulence u pat 7-8K... it might be the spark plugs or the ignition coils actually... Before I bought my car, I actually test drove it and it really didnt want to rev pas 6K, and it made a LOT of vibrations when you got there. When I finally got some money to buy hte car a few months later, I was told that it got check out by a mechanic and the plugs were badly frozen in and extremely badly fouled. With the new plugs, it pulled real nice to 8K and felt like it hade a nice flat torque curve. Check your plugs tasty....

As for your weird electrical problems, I think the ECU are reputed to have poor solder joints on it... so you get stuff like the E-Brake light always being on, or the seatbelt thing beeping intermittantly... maybe check your ECU solder joints. I think stock ECU's are fairly common and you can probably get one pretty cheap, if not even borrow one from a friend and try it out.
You could try resetting your ECU also, see if that helps... disconnect thenegative battery terminal for 5 mins and then plug back in.
Also try checking your engine check codes, there is a thread somewhere around here that has a link to a site with a complete list of how-to and the codes.

 

I guess I'll start with the plugs and a rad. test. Checked the BAC- moves freely, is pretty clean. Thanks for the help so far, and any other suggestions would be appreciated.

 

ttt....anyone else?

 

might want to try to check for a small vacuum leak with a can of carb cleaner or starting fluid.

 

I get a major stumble at 7500 rpm under load. I thought it was the rev limiter though. Hummm