MAP - any particular brand? Anyone else

[Ramblin Fever]

ever have to replace one?

Must be a fairly common failure part, round this neck of the woods, as I can rarely if EVER readily find Napa having a part in stock - just so happens they have 4 in stock. I was blown away when I called them this afternoon, as I expected it to be in in a couple days - not readily available.

Which lead me to wonder if it's a common issue on 96-97yrs anyway...Anyway's I don't remember ever reading about an owner having to replace theirs, but I've never actually searched it out either.

Anyhow - they have a standard MAP - my guess is lower quality then OEM; aftermarket high performance (???) MAP; an original OEM Map Sensor; and I forgot the other one he mentioned.

Are all MAP sensors the same though - I mean, what does an aftermarket high performance MAP sensor mean in this situation??

FWIW - mine is completely fried; does not give out any voltage reading.

EDIT to add: price isn't all that bad. $35 for standard; 44 for OEM; and $6? for high performance. Haven't bought it yet, wasn't sure which one to get - but I'll need to get it tomorrow, truck's idle is getting really rough, though the CEL is off again - which is weird.

[Cat Fuzz]

High performance my kiester. Get the cheap one. They're probably all made by Delco/Delphi anyway. I've never had to replace a MAP sensor in any car, yet. Knowing how MAP sensors work and their function, I don't see how one could be "high performance".

BTW, did you make sure there was the required 5 volt input voltage before condemning the thing?

[Ramblin Fever]

Yeah.

I was wondering if they were all the same - thanks.

[rodeo02]

Ramblin are you replacing the MAP sensor in the hopes it makes the EGR related CEL go out? If it's a cheap and easy part to replace, why not. I wouldn't go thru the bother if it's expensive and hard to replace. A failed MAP sensor would give it's own code and some pretty serious performance concerns.

Joel

[Ramblin Fever]

It's cheap, sits on top, whether or not it's giving it's own code, I don't know. But you had mentioned in my other post that the MAP is most likely what tells the EGR valve when to operate currectly.

[rodeo02]

Originally Posted by Ramblin Fever

..you had mentioned in my other post that the MAP is most likely what tells the EGR valve when to operate currectly.

I think what usually happens in those type systems is: Upon startup at idle, the PCM commands the EGR to open. If the EGR opens and flows as it should, the MAP sensor picks up the drop in vacuum caused by the pressurized exhaust being fed into the intake manifold. Some systems also look for a drop in RPM as they kick open the EGR. If the PCM sees that blip in idle, it figures the EGR is being bled in. IIRC- the feedback or digital EGR valves read a temperature delta across the valve. That's how they know if they are flowing or not.

Joel

[Ramblin Fever]

Well, FWIW - have not replaced MAP, in fact, haven't even bought it yet. CEL is off for 2 days now (almost) and truck is running perfectly.

So where do I turn next - should the evil return?

All connections are good/clear, EGR valve is new, that DPFE sensor doesn't exist per the Isuzu dealership, they don't know what I'm talking about and according to them Isuzu's don't have one. And, of course, that doesn't mean they know what they're talking about - but does anyone else know if the '97yr has the DPFE sensor and where can I find one.

I've looked all over the internet - they have them listed as parts for other vehicles, namely ford, but can't find a single one listed for Isuzu anywhere.

Are ANY other sensors related to this EGR valve insufficient flow; i.e temp sensor, idle air control, etc

[rodeo02]

Rambin, just for reference sake, I wish we could get ahold of a factory wiring schematic for the 1997 3.2's EGR system. Atleast that way we'd know if it's a feedback system or if it needs to read the MAP, idle speed, etc. I gotta think yours is a feedback like the 1998+, but dunno without a schematic.

Joel

[Ramblin Fever]

Wonder if we could get 2eyefish in here; he would know. I'm actually surprised he hasn't responded, been on board last day or so.

I'm thinking about sending him a PM - gonna get some shut eye for now though, new job's got me running on empty.

Thank you for your help in this - probably just as nerve racking for you as it is me.