Cold Start Issues

[MuddQueenK5]

I will start out my story with every morning or when I leave for work and I start the car cold I have acceleration issues. When I go WOT (wide open throttle) it will sputter and sometimes (but rarely) stall out. Another thing, when I am on the gas when sputtering the transmission shifts hard from 1st to 2nd. The car actually lunges forward during the shift and you can hear it go *clank*.

Specs on Truck:
1988 Blazer K-5 (completely stock)
TBI
Automatic Transmission (NP208)

This is what I have replaced/cleaned:
Spark Plugs (AC Delco)
Spark Plug Wires (MSD)
Cap/Rotor/Air Filter (OEM)
Fuel Filter (OEM)
Additive in gas tank to remove moisture
Fuel Injector Cleaner
Throttle Body Cleaner
Seafoam for PVC/TB

Also, when going above a certain MPH my "Service Engine Soon" light pops on. When I am slowing down/idling at a light it goes off. I have checked all my fluids/vac lines and everything seems fine. I went to my local Advanced Auto to try and pull the codes with their OBD I GM reader, but it wouldn't pull my codes. The reader just kept saying that it wasn't plugged into the diagnostic port when it was. When the car is warmed up I have no WOT issues at all, no hard shifting from 1st to 2nd, it just idles low. Any ideas? Thanks

 

[chevyk2500hd]

I might vote for a bad 02 sensor. If it doesn't heat up properly then the motor might run in a open loop situation. Cold weather may also make it take longer for the 02 sensor to heat up. Also I wouldn't recommend going WOT on a cold motor. Damage can occur with cold engines because of a lack or good oil circulation. That is just my 2 cents.

 

[MuddQueenK5]

I might vote for a bad 02 sensor. If it doesn't heat up properly then the motor might run in a open loop situation. Cold weather may also make it take longer for the 02 sensor to heat up. Also I wouldn't recommend going WOT on a cold motor. Damage can occur with cold engines because of a lack or good oil circulation. That is just my 2 cents.

The people behind me are not going to appreciate that....but I will try changing my o2 sensor and see if that helps any.

 

[chevyk2500hd]

Also you should be able to check engine codes with the engine light. I would have to check my gm service manual but on my truck you short to pins on the OB1 connector and the engine light will flash the codes.

 

[lamberthkp]

agree, check the codes yourself on that connector take a paper clip or wire and stick in the top right terminals to connect them , turn the engin key dont crank it just turn the power on . it will flash each code 3 times and until done then start back over. the first code that will flash is 12 flash.......flashflash like that , if you have a haynes manual you can check them in the back of it or call auto zone to see what they meen.

 

[opfor2]

I'll bet it's the EGR valve thats either stuck open or wont open when needed. A stuck open EGR valve would/could cause starting issues.

Dan

 

[MuddQueenK5]

Update: I replaced the o2 sensor last night and the orignal I got out by hand. I bet that didn't help the situation at all so I installed the one and also checked my spark plug wire connections. Everything was solid and the car idled perfect. I took it to work this morning and everything seemed to be up to par no stuttering until I was stuck at a light waiting for the train. When I went to hit the gas same deal, it had a difficult time accelerating and was sputtering.

I went searching on this site on replacing EGR's and I see a couple members suggesting to just take it off and spray carb/tb cleaner on the bottom of it and just clean it? Should I try that or just replace it completely?

 

[dyeager535]

Quite a few folks have solved EGR issues by just pulling and cleaning them. Also if the intake is plugged, breaking that out/vacuuming it wouldn't hurt.

Making sure it works correctly and is clean can't hurt anything, replacing a good piece will cost you money.

I believe your '88 will have an EGR solenoid, you can always disconnect that as well. Pushing up on the underside of the valve while the engine is running should hurt idle, but once you let go, if the valve seats, idle should be fine.

WOT ignores O2 sensor, (not to mention it's on a timer for cold engine starts, depending on if you let the vehicle warm up or not) so that could never be the sole cause of your problem. EGR is not used during acceleration either, but bad components in the EGR system could still cause problems.

 

[MuddQueenK5]

So, if I am understanding you correctly, the EGR solenoid itself is not the problem to my sputtering? And while the engine is running pull up on the valve and release to check if it's bad or not?

Should I go forward and try to clean the solenoid anyways? I am not sure what else could be the culprit since everything ignition wise has been replaced.

 

[opfor2]

Well you really need to test the EGR valve to make sure it's operational. There's no point in pulling it off, cleaning the ports and the needle valve and then replacing it with a NEW gasket just to find out later that it's defective. U need to hook up a small hand operated vacuum pump to it and watch the diaphragm and needle valve for movement. It should also "HOLD" vacuum for several minuets if the valve or diaphragm doesn't move replace the valve. BUT, do your self a BIG favor and get a REAL AC DELCO valve not an aftermarket one. Trust us on this many of folks have replaced there EGR's w/aftermarket one's only for them to fail months later.

Dan..