CEL, but not overboost

[Dieselpwrdredneck]

OK if im goin down the highway, and mash it i will get a check engine light, truck has a different sound, and a little laggy, couple minutes the light goes out and back to normal, but im pretty sure im not overboosting unless my boost gauge is broke. never got a chance to read code b/c i dont have a reader.

What could this be?

Thanks guys
Neal

 

[JLDickmon]

sounds like mine... I got an injector that won't switch low/high when it's cold... once it comes up to operating temp it's ok...

better get it scanned for codes

 

[Dieselpwrdredneck]

This will do it at all temps. it feels like im tripin a senser, and its defaulting back to a preset setting or somethin.... i dont know

 

[JLDickmon]

get the codes scanned..
we need to start there.

 

[BIG JOE]

OK if im goin down the highway, and mash it i will get a check engine light, truck has a different sound, and a little laggy, couple minutes the light goes out and back to normal, but im pretty sure im not overboosting unless my boost gauge is broke. never got a chance to read code b/c i dont have a reader.

What could this be?

Thanks guys
Neal

When you Mash it.. momentarily your over-boosting. the MAP sensor detects that.. (CEL comes on) and sends a over boost signal to the PCM... the PCM attempts to cut boost by going into whats called: a De-fuel mode or, cuts the flow of fuel some (Laggy feeling). After a few minutes... the CEL goes out, the PCM goes back to default setting and you motor on.

What you need is: A Boost Pressure Relief Valve (BPRV) or, some like a little electronic Wizzo thingy that does the same thing: Tricks the MAP sensor into not sensing Over-Boost by bleeding off boost pressure before it gets to the MAP sensor.

Yer lucky. Most Over-Boost cases SET a code. The CEL stays on, The PCM stays in the De-fuel mode.. until you erace the code with a scanner or dis-connect the Batts for 30 minutes, or so.

 

[JLDickmon]

Yer lucky. Most Over-Boost cases SET a code. The CEL stays on, The PCM stays in the De-fuel mode.. until you erace the code with a scanner or dis-connect the Batts for 30 minutes, or so.

if the CEL illuminates, even for a split second, you've set a code.

 

[BIG JOE]

if the CEL illuminates, even for a split second, you've set a code.

True. It will set, or record a code, in the erasable memory that over boost occurred. But sometimes, depending on year, PCM series, after a few minutes, or start cycles, the PCM resets from the De-fuel mode. CEL goes out, truck runs fine.

On my 2K, if the CEL came on, it stayed on and stayed in de-fuel mode til I dis-connected the batts, pulled fuse # 15or erased/reset it all with my scanner. Other 7.3s Ive wrenched on ? I've found codes but the truck was running fine..

 

[Got Diesel]

It could also be a P1211 code with is ICP pressure above or below desired. They will come on with a chip. And will go off but it takes a little while usually.

 

[fgtex]

It could also be a P1211 code with is ICP pressure above or below desired. They will come on with a chip. And will go off but it takes a little while usually.

This is the deal with my truck. I have the overboost fooling device from ITP. My truck sets the code that the HPOP can't keep up. The CEL will go off after about 15 mins of driving if is does not catch it again. I went to AutoZone the last time that it came on and it did not come up as a stored code when they pulled the codes (CEL went off before I got there). I guess you could race to AutoZone and set it on the way and have them pull codes while the light is still on.

 

[Got Diesel]

Autozone Scanners won't read anything on our trucks. Trust me the code is still in your pcm.