DFI and ECMDiscuss all aspects of DFI (Digital Fuel Injection), ECMs (Electronic Control Module), scanners, and diagnostic equipment. Fine tune your Third Gen computer system for top performance.
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Hi Guys, I'm actually posting for my dad, its his car, so I'll try to describe the problem he is having. Its a 88 IROC 350 TPI, pretty much all stock with 110k on it. He's been having an intermittent problem lately, the car runs really, but when he's coming to a traffic light or stop sign etc the idle will start to get rough and then it will stall out. Once he stops and puts it back in park it will start right up and run fine. He said it happened to him twice yesterday and wanted me to see what I could find out about it. I'm going to borrow a scanner from a friend sometime this week, but figured I would post to see if you guys know of anything obvious we could check. I apologize in advance if this is the wrong section to post in, any help would be appreciated.
Thanks
Sean
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Use a scanner you can have connected while driving the car to see what it is doing when it stalls and check for codes and post back and any one could help you better because somany people have been having the same problem but different fixes and some are still trying to fix the problem .
__________________ Mighty 2.8 power . Enough said .
Alright, I'll have to get my hands on a scanner and see what codes pop up, as for the temp I'm not sure, but I'll ask him if he remembers. After it stalls and is restarted it idles smoothly like normal and doesn't seem to have any problems.
possible vapor lock if the car is gettin to hot and the gas starts boiling. i know it can do that with a carb so i would assume it would do the same with any other.
I'm glad you said that! It was the first thing that came to my mind, but he didn't seem to agree, glad to see I'm not going crazy haha. I haven't had a chance to talk to him since posting (he works nights, I work days, our paths don't always cross) so I haven't gotton any more details from him.
Thanks again for all the replies guys.
Keep it simple... Check things that are easy to tinker with before you decide to go looking into torque converter issues.
The FIRST thing that I would do is check the air delievery system. Clean the throttle blades and the bore of the throttle body. Then, pull out the IAC and clean the IAC passages to make sure they arent all carboned up. In fact, pulling the throttle body off and giving it a good cleaning all over isnt a terrible idea.
You can check things out with a scanner, as long as its a good one that can check all the systems and work while the car is driving. Chances are, if you arent logging or watching the scanner right when it happens, you wont see it. Especially since its firing right back up.
Also...keep this in mind. IACs can go bad and NOT throw a check engine light. Ive had it happen twice. Once in my 87 TPI car, and once on a 96 Grand Cherokee. Those things can get carboned up and stick. Especially if the car sits. My TA was having a high idle condition... And the Jeep was stalling out when coming to a stop. But would always fire right up, because the IAC resets when you restart the car.
Just something to think about. Check it, maybe toss another one on there to see how it acts. Check all your vac hose connections and what not. My TPI always gave me fits beacuse its not as easy to scan as an OBDii car, but has just as many, if not more, sensors and do-dads.
Good luck.
J.
__________________
ARE shortblock, Ross custom boost pistons, arp rod bolts, ARE ported oil pump,
MTI 2e 5.3L ported heads milled .030 with double springs,
228/224 113+1 Comp XE-R, Cloyes adjustable timing chain, LS6 valley cover,
fast 90mm intake, NW 90mm throttle body, SVO 30lb injectors, 85mm MAF,
ASP underdrive pulley, 160* t-stat, stainless LT headers 1.75" primaries
IAC could be the culpret but a good scanner will let you now any and all problems . And some codes do not set a light untill they happen to fail often so there may be codes stored awaiting to light-up the check engine light .
__________________ Mighty 2.8 power . Enough said .
IAC could be the culpret but a good scanner will let you now any and all problems . And some codes do not set a light untill they happen to fail often so there may be codes stored awaiting to light-up the check engine light .
I'd change any and all to "some", this is an obd1 system we're talking about..
Its like trying to talk to a caveman compared to OBDii. You'll get some info, but its vauge and you'll have to interperet most of it.
What? I wouldnt go that far, sure it doesn't spell out the problem exactly like OBD2 (find one good mechanic that starts replacing parts, and spending money, just off what OBD2 says and I'll show you a man about to go out of business) but anyone that knows what their doing will be able to use the data to atleast narrow down the problem. Its about a million times better than not scanning it and just guessing.
Haha...paper clip is considered entry level. Piece of bent wire is your bottom basement bargin tool. Haha. I used to keep paper clips in my car all the time when I was TPI.
Drumer919: Most people dont know how to get the info from an older computer system. Unless they have a good scanner, and know how to use it, its not going to be of much use to them. And places like autozone cant do much with obdi systems other than read your codes. When I was a manager at Autozone, I ordered in a "Genesis" scanner for about $3000. That thing was awesome. It would do just about anything. The person that wanted it decided they didnt want it...so I kept it around the store until inventory time. Anyway. With the OBDi systems, it was still somewhat of a pain to get your info. With OBDii it was a totally different tool. You could see everything in neat little graphs and readouts and you could manipulate things like idle and door locks. Just so much better.
I agree...replacing parts just beacuse there is a code isnt very smart. However, replacing parts after you use your noggin alittle, especially after getting a code for the part, isnt so dumb. Point being...the IAC. Im not even sure a scanner would pick up on a sticking IAC. It might...Im not sure how much info the OBDi systems spit out about them. But even with out a code, its not a terrible idea to try to replace it. They arent completely electronic. There is a mechanical aspect to them that tends to get jacked up and not work right. Thats just speaking from experience though.
But I digress...we're getting a good bit off topic and I dont wanna bugger up the thread. Did the OP get this straightened out for his dad? Or still having issues...
Did you do preliminary checking before replacing? Check all your vac hoses and connections? Clean your MAF sensor? Check your throttle body blades and IAC passages?
You guys are having the opposite problem that I kept having with my old TPI motor. That thing would idle high no matter what. At one point it would almost do a powerbrake on its own it was so bad. Then, one day, it just went away and never came back. haha.
Definitely seems to be a common problem... My '89 had the same thing. Stalling when coming to a stop. One other notable thing was that whenever it was going to give you stalling problems, the idle would also be bad. If I started it and the idle was low, it would stall @ stops. But, if idle was normal at start then all was well.
IAC was my first suspect as well, but the car went into the garage for T-top seals before the stalling issue was ever really looked into. That was over a year ago... Seals still aren't in, ....
Anyway, I'm going to subscribe here just to see what ends up being the culprit for this one...
-1989 Camaro with a 305 TPI, soon to be 6.0L LSx. -1985 Camaro with a 350 TPI, probably gonna stay that way. At least until I'm done with the other one...
FYI all, My 91 speed/density system developed a very high idle (1500 to 1800) after initially having a low idle stall out issue on decel. My first reaction was to replace the IAC motor with a junk yard freebie which made no difference. Linked up with moates free and saw that the TPS was not sending data. Problem solved. Maybe this will help.
. Enough said . 
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