88 seems to be cutting out while driving

[badabing9]

hello,
i am new to all this so, if i screw up, somebody tell me! anyway, i have an unmodified 88 vette that in the last 2 weeks has seemed to develope a minor and barely noticable miss only detectable at idle or in drive with vehicle not noving. in the last 2 days, the car, while doing 50mph seemed to "cut out" while driving. the ses light came on momentarily and then quickly went off. there are no codes displayed.

recent tune up (ecept for the fuel filter which i understand may have been replaced by previous owner), cap, rotor, ignition module, plugs. less then 100,000 miles and in spectacular shape. i have noticed that the lock-up on the transmission (automatic) was engaged when i accelerated from a standing start and the point where it would normally engage (41-44mph) at one point, seemed to actually been a bit higher then normal although, this could have been my imagination.

my first guess is that it is something under the dist. cap, possibly the ignition module. my next guess is that maybe there was some "crap" in the tank. next would you say maybe the main computer for the car? i thought about the maf sensor but, am throwing no codes. fuel pressure is steady and in the normal range.

i have just come in from resetting the timing. i had unplugged the est connector as described in the helms book while doing this and engine was at operating temp.. i had also reset the computer by unplugging the "double red" wires near the battery that are supposed to interrupt power to the computer while not disturbing radio presets, etc..

***i had noticed that those very same wires nearest the battery are abnormally hot to the touch which alarms me! while i am not blowing any fuses or anything, is this a sign that my computer is bad or going bad?

anyone with any ideas?..thank you.

 

[Edmond]

You should check for the codes even though the light turned itself off. The codes will stay stored in the computer even though the light turned off. However, since you reset the computer, the codes are probably gone.

You can check the codes yourself. IIRC, you just jumper the top two plugs on the right side on the data link convertor located underneath the driver dash. Then you turn the ignition on, but do not start the car. The SES light will flash codes. Count the codes and we can tell you what's going on. Codes will flash 3 times before it goes onto the next code, if there is a next code.

 

[badabing9]

You should check for the codes even though the light turned itself off. The codes will stay stored in the computer even though the light turned off. However, since you reset the computer, the codes are probably gone.

You can check the codes yourself. IIRC, you just jumper the top two plugs on the right side on the data link convertor located underneath the driver dash. Then you turn the ignition on, but do not start the car. The SES light will flash codes. Count the codes and we can tell you what's going on. Codes will flash 3 times before it goes onto the next code, if there is a next code.

thanks for reply. darn it, i did not think of the stored codes at the time! go figure! any idea as to why the (i assume) power wires to the computer are getting so hot? thanks again!

 

[nyernga]

Your best bet is to wait until it throws a code again and THEN see whats up. I have an 88 service manual so if you need help reading the codes, deel free to pm me.........


Len

 

[Vettefan87]

If the car has a lot of miles on it, you might want to look inside the TB at the butterflies and see how dirty and grimy they are. This has sometimes led to a slight miss.


Justin

 

[badabing9]

thanks for your support.
i can probably see how a dirty tb can cause a miss but, not at all for a complete "cut-out" i will wait for the next "fault" and go from there. any idea how much another computer costs for this? has anyone ever determined why the wires are getting so darned hot as mentioned in my original posts? i think i am gonna put an amprobe on it today to see what the draw is. can the tb be cleaned using products like gumout or over the counter tb cleaners (spray)? thanks again

 

[Edmond]

You have to pull the codes first and it will tell you if the computer is bad. As for the wires getting hot, some of those wires do get hot while they're being used. As for how hot, I couldn't tell you.

The computer chip box for example, gets pretty hot and makes noise. I've driven with that computer box kind of exposed with the under dash cover off.

 

[taegdh]

Misses at idle, on a 14 year old car, there could be lots of things.

Even if the previous owner did change the fuel filter, it's cheap and can be done in an hour. Don't let the fuel get too low, (1/4 tank), or you'll fry the fuel pump.

With these fuel injected engines, the old adage of "Cleanliness is next to Godliness!" applies fully!!!! The throttlebody, EGR Valve, MAF Sensor, TPS, all the fuel delivery parts.

You didn't mention the last time the Plugs and the wires were replaced. (Did you relpace the looms also?) Cheap but they keep the wires from being crossed, and if they're crossed, under heat and weakness in the insulation is present, that'll do wonders for you trying to track down a miss...

Lots of Luck!

 

[badabing9]

hello all,

update....i think i found the problem. the car "cut out" again which enabled me to pull a code. it appears that the new ignition module i put in in august of this year went bad. i replaced it today and all appars well, or at least the curb idle as i have not road tested it. as for wires, plugs, cap, ignition module - all were replaced in august of this year. i have fuel filter but, have had time to replace it yet. wire looms-holders are fine, no crossed wires and no arching at night and original from what i can make out. wires howerer, have not been changed yet. i took a look at them and man, it appears to be a job to replace them! i will probably do something stupid and wait until they star "crapping out". yea yea, i know! the wires powering the computer as a cool as can be for some reason. believe me, i am not complaining. picked up a workig computer from a friend at no cost today, sorta as an emergency spare..............thanks again.