Flash code and engine starting problem

[Helmar]

Hi all.

 

I am wondering if anyone has had either one of these problems.

One might be related to the other?

 

My truck is a 1988 GMC with about 238k and on the second engine.

It’s a 1500 half ton stepside that I made into a full size low rider several years ago.

It has the EFI carb setup, 350V8, auto, air – well, its got everything.

 

The first problem started quite some time ago.

When in Overdrive, it seemed to take a long time or lots of slow down and pressure on the gas peddle to get it to Kick into a lower gear. That I just lived with.

 

Then all of a sudden, I noticed the break light, service engine light on.

I figured I had better check the brakes again as its been awhile.

Then the next day, that light started blinking.

It would blink 3 times fast, then 1 slow.

Best I could figure out searching the web was it was three flashes, pause, three flashes.

 

I had stopped at the store on my way home and just did a quick in and out.

When came out, it started but then almost died, like it was not idleing fast enough?

As soon as I pressed on the gas, it seemed to come right out of it meaning the RPM’s came up to normal.

 

When I got home and parked it to unload, all was fine. I got back in the truck and went to start her up and she would start, but then just die, start and die.

It was like as soon as I would let go of the ignition switch, she would die.

 

SO, off to the web looking for codes again.

 

In looking at the codes, it shows to be code 33, map sensor, SO, I marched up to the local NAPA store and paid way too much for one and installed it.

I tried to start up the truck and she did the same thing.

It would start and then just die.

 

After scratching my head for a few moments, I realized that at the store the day before when she was acting funny, the RPM’s did not increase when I started it?

SO, I got back in the truck and this time, pressed down on the throttle like I would on my old Dodge van to get her to start. Sure enough, she started but when I released the throttle, she died.

I tried it again but now This time, I noticed that she started and the engines RPM’s were up like it should have been on a cold start.

 

Before, even warm, the RPM’s would rise up above idle, the settle down but something was causing her not to do that.

 

Blab blab blab, too long of a story but does anyone have an idea on what might be Not working to cause this?

 

The engine is pretty clean, everything moves as it should, meaning nothing sticking or hung up.

 

Any help?

 

Thanks.

Helmar

[getcrunk88]

I am pretty shur that i know what your problem is its called the iac "Idle air control valve" controls the amount of air that is taken in at idle and the tell tale signs of a worn or sticking iac is exactly what you said your problems are . The good part is that it is not a really expensive part running around 30 bucks and a pretty quick fix here is a link to the part.

http://www.partsamerica.com/ProductDetail....ype=757&ptset=A

[Helmar]

I am pretty shur that i know what your problem is its called the iac "Idle air control valve" controls the amount of air that is taken in at idle and the tell tale signs of a worn or sticking iac is exactly what you said your problems are .  The good part is that it is not a really expensive part running around 30 bucks and a pretty quick fix here is a link to the part. 

http://www.partsamerica.com/ProductDetail....ype=757&ptset=A

 

<{POST_SNAPBACK}>

 

 

 

Hi Alex.

I had no idea they even had critters like this on this new stuff but I am an old Old line mechanic from the 70's.

 

I went to the link and looked at the IAC, then went to my truck and started looking for it on the Intake manifold? I will have to go back out and look harder as I didn't see it as of yet.

 

I kind of miss the old car repairs as I still have a few of them I can keep running with no issues.

My old 76 dodge van is almost too simple to work on.

 

Its really hard on this new stuff when one knows what is wrong but no clue on how or what controls it.

 

That code thing had me going as it had three flashes, pause then three again and that said Map sensor.

Like I said in the Long post, once I put my foot on the throttle and gave her just a tad, she started up and ran.

At this point, she seems to be good and fine but if that sucker is sticking she will sure as heck fail me when I least expect it.

 

Back to looking as I forgot to look on the Carb base for that IAC

 

Thanks Big time for your reply !!!

 

Helmar

[getcrunk88]

No problem Helmar, I looked up exactly where your iac valve is and its exactly where mine is, UNDER HOOD, CENTER, UPPER ENGINE AREA, MOUNTED IN PASSENGER SIDE REAR OF THROTTLE BODY UNIT if you ever need to know where parts are on any car you can use http://www.autozone.com/ go to repair info and click on component locations type in all of your specs about the car and then just type in the part you are searching for this comes in handy alot for me because working on some jap cars things can be hidden pretty well and i use that site to search for location of parts.

[Helmar]

No problem Helmar, I looked up exactly where your iac valve is and its exactly where mine is, UNDER HOOD, CENTER, UPPER ENGINE AREA, MOUNTED IN PASSENGER SIDE REAR OF THROTTLE BODY UNIT if you ever need to know where parts are on any car you can use http://www.autozone.com/ go to repair info and click on component locations type in all of your specs about the car and then just type in the part you are searching for this comes in handy alot for me because working on some jap cars things can be hidden pretty well and i use that site to search for location of parts.

 

<{POST_SNAPBACK}>

 

 

 

Good advice Alex.

Thanks for your help as I went and picked up one from Napa and everything seems fine now.

 

Well, I still have that shifting issue to deal with.

I might make a post about that.

Seems to me that happend after they replace the engine with the new one so I am thinking it might be a linkage issue.

 

Thanks again.

Helmar