car is an 88 LO3 auto cali emmisions...

step by step

cold start is fine... goes up to 1750 and idle down over a few mins in gradual steps...

get out on the road all is good... runs fine at normal steady cruise...

gets up to normal operating temp...

normal cruise still fine... but get in it a bit and has some predetonation...

get to where ever after 20 mins of driving... go inside.... come back out 20 mins to say 1.5 hrs later...

car fires right up... goes to high idle... but when it tries to settle it starts to surge and eventually dies...

to get it to stay running gotta play with the accel pedel till it catches and will rev over 3500rpm... at this point it surges (in park car stationary) and eventually settles down... now it will idle on its own...

get rolling through the parking lot and it wants to cut out... if I get into the accelerator it starts to clear up... this goes on for a couple mins...

if I'm drivin in stop and go traffic at this point it acts like it lacks power and cuts out abruptly...

get out on the open road and it act normal at a steady cruise... still has pinging when gettin into the throttle a bit (doesn't take much, any thing over a mild hill it will start after the TCC kicks out...

car has 170k on it... good steady vacuum at idle 21inhg... get an occaisional code 32 at steady cruise highyway speeds... plugs look fair, cap, rotor, plugs and fuel filter have been changed... on secondary inspection all look fine... replaced distributor and coil with known good ones and no change... fuel cone from injectors looks fine... checked battery and chassis grounds and pos all look ok... also fuel trim numbers at steady cruise unde mild accel seem to be a bit high... some times way high...

not sure if the EGR could be doing this... seams it should not fuction at idle... if someone could check a data base for me on that it would be great...

when I start tryin to diag this thing it won't cooperate and consistantly reproduce the problem... heh...

 

The EGR valve shouldn't be open at idle, which is probably why you're having problems.

Cleaning or replacement most likely required.

 

I figure if it was sticking open then it would have issues consistantly... when it gets over its fits, it still pulls good idle vacuum...

is there any reason it would command the egr valve to open on hot start before it goes into closed loop??? even a diagnostic funtion???

 

It can stick intermittently.

 

the hot start issue is very consistant... I can mess with the diaphram on the EGR valve right before the initial crank of the problem and it does not affect it...

 

Let's give Shifty & Company a shot at it over on the TBI forum.

 

cool... all help is welcome...lol

 

How old is your 02 sensor? They tend to go out without throwing a code or giving any serious sign that they have headed south. If it has been there awhile it is a good idea to replace. These cars love preventative maintenance. 99% of all GM vehicles with EGR will throw a code sooner or later on highway driving. Exercise the diaphram and make sure it is not gunked up with carbon.

 

O2 sensor has about 5k miles on it... on a scanner it reacts great... swings back and forth across 450mv nicely...

have moved the egr diaghram around and it moves freely...

 

You haven't by chance fooled with the IAC have you? With excessive amounts of carb cleaner or anything. Have you checked your TPS voltage as well.

 

TPS voltage at spec... nice voltage sweep... have not touched the IAC... seams to work fine on cold start and once it gets over its hot start fits...

I haven't really watched the IAC steps on the scanner... just cuz if it were an IAC prob it would most likely be doing it at all temps..

before it stalls on hot start it seems like the IAC is trying to compensate...

 

have you outruled any small vacuum leaks? Follow the vacuum lines from the TBI unit and pay attention to those that run to the MAP sensor. Even a tiny hole can cause a surge.

 

What does the scan tool say on the engine temp. If the temp sensor is going bad it could cause the engine to run rich on a hot start up. It could be telling the ecm that the coolant temps are lower than they really are. Cold start up would act normal then get worse as the temp comes up. Just a thought.

Steve

 

been all over it... everything visual looks fine...

 

Steve brought up a good point. You may want to test your CTS to make sure it is reading correctly. There is a diagram that shows the correct resistance per termperature. A quick search should find it for you. You would need to pull it and use a pot of hot water and test the resistance at certian temps of the water. It is a cheap and effective way of testing it.

EDIT: I found these values with some searching.

Deg. F - Ohms
212 - 177
210 - 185
194 - 241
176 - 332
160 - 450
158 - 467
140 - 667
122 - 973
113 - 1188
104 - 1459
100 - 1800
95 - 1802
86 - 2238
77 - 2796
70 - 3400
40 - 7500
20 - 13,500
0 - 25,000

 

all sensor readings look good on the scanner... nothing out of the ordinary accept for fuel trim...

blm and int go way up... into the 140's at times... I'm waiting on a fitting to verify fuel pressure but at this point I'm leaning away from that...

if ya have any info for diag on the EGR for an 88 LO3 w/ cali emmisions or any service bullitens that might show this prob I would very much appreciate that...

 

If you PM Trickster he can send you pages right from the GM shop manuals. Pretty helpfull stuff.

 

ok... lookin for diag procedure for the EGR at this point...

car is: 88 LO3 auto cali emmisions

hot start surge then dies...

gotta play with the throttle and get it to hang steady at 3500 rpm before it will idle on its own...

after that it lacks power severely till it completely clears up on steady cruise and the temp come down...

still has moderate predetonation at this point on open road...

 

Ignition module in distributor.

Fuel pump.

 

Mine does the same thing too. I have the same set up with engine and tranny and its an 89, but a pro/am (no biggie anyway). If the temp gets over 220 (the most was 240) the car will start but die immidiatelly. This is because of the starter being exposed to soo much heat, and its a plague to our "hot" starts. Now, I know I am just addressing one of your problems, but its the only one I think I can help with.
Do the remote starter mod if you dont want to mess with your cooling system. Ya, the cooling system will keep your car cool and you would not have to worry about the hot starts. Also, at what temp is your car running at??? If above 220 you gots problems. I replaced my whole cooling system and the hottest I ran was 200. (mind it, it was a 100weather in hour stop and go traffic). So, keep the beast cool if possible, however if you dont have the dough than get the remote starter.
For your other problem it does sound like a stuck EGR valve, even if its not, replace it anyways.
Good luck.

Check your vacums again.