Check engine light

[Gazz]

Hi all, looking for some help. I decided to do some general maintenance in the form of cleaning the MAF sensor, throttle body and IAC valve and since putting it all back together my check engine light has come on. I'm pretty sure I've put it all back correctly, reconnected all the sensors and I don't think anything broke or cracked in the process.

Any suggestions?!

1998 4.0 V6 SOHC

 

[XLTrunner]

Time to pull out the scanner and check for which code/codes are being set. Did you install new gaskets when you reinstalled the throttle body and IAC?

 

[koda2000]

If your check engine light is ON there is no way to know what the problem is unless you scan for the specific code(s) that are set. If you don't have a ODB II scanner, most auto parts stores will scan your codes for free. Ask for a print out afterwards and report back.

 

[Gazz]

Time to pull out the scanner and check for which code/codes are being set. Did you install new gaskets when you reinstalled the throttle body and IAC?

Didn't install new gaskets, do think it might sucking in extra air?

 

[Mickalo]

yep like mentioned above need to scan for any codes may find issues with fuel trims if your sucking in un-metered air from bad gaskets.

 

[XLTrunner]

It's always a good idea (and, cheap insurance) to use new gaskets as the old, original ones have hardened and taken a "set"...potentially causing air leaks. But, it's difficult to recommend further action until the codes are pulled.

As mentioned, most auto parts stores will still let you borrow a scanner.

 

[koda2000]

It could be gasket related, but I've reused the IAC and throttle body gaskets multiple times and never had any problems with them leaking. Again - no way to know what the real problem is w/out scanning the codes. You can buy an inexpensive ODB II scanner for under $50, though a more expensive one will give you more information. It's a good tool to have, but having the auto parts store scan your codes doesn't cost you anything.

Curious, how did you clean the MAF sensor? Did you use MAF cleaner? Did you touch the element with anything?

 

[Gazz]

It could be gasket related, but I've reused the IAC and throttle body gaskets multiple times and never had any problems with them leaking. Again - no way to know what the real problem is w/out scanning the codes. You can buy an inexpensive ODB II scanner for under $50, though a more expensive one will give you more information. It's a good tool to have, but having the auto parts store scan your codes doesn't cost you anything.

Curious, how did you clean the MAF sensor? Did you use MAF cleaner? Did you touch the element with anything?

I'll look into getting a scanner, I'm slowly discovering that parts and equipment for these trucks are not easy to get hold of in the UK! I'll also look at replacing the gaskets just in case.

Didn't touch the element at all, gave a few quick bursts with MAF cleaner as prescribed and from what I could see that seemed to clean it up nicely.

 

[koda2000]

I'll look into getting a scanner, I'm slowly discovering that parts and equipment for these trucks are not easy to get hold of in the UK! I'll also look at replacing the gaskets just in case.

Didn't touch the element at all, gave a few quick bursts with MAF cleaner as prescribed and from what I could see that seemed to clean it up nicely.

You may not need to purchase any new parts. More than likely something you did while doing your preventive maintenance is the source of your check engine light. Have you rechecked the hoses related to the PCV valve? The PCV valve on these engines are very difficult to change, especially on the Job 1 engine when the rubber hoses get old and brittle. The PCV elbow is a known common source of vacuum leaks because it deteriorates and cracks and/or collapses. ODB II scanners should be the same in the UK as in the US. It shouldn't be difficult to find a scanner or someone who has one.