No acceleration after head gasket replacement...

[n8thgr8]

Hey guys.
So, '98 d1 gems 4.0.
I'm searching for info on behalf of my mechanic I'm still in Guam, so I'm tying to help out this shop with as much information as I can.
He's done the head gasket replacement, ground the valves and replaced the valve seals.
He is telling me that it starts, but doesn't have power when accelerating.
Any clue where to start looking for solutions? I'm at a loss.
I don't have the truck, and unfortunately that's all the information I have right now.

 

[Flyfish]

Have him give you compression #'s for each cylinder. Ideally, you want less than 10% variation.

If they're good, have him take an infrared heat gun and compare temps on the Y-pipe both before and after the cats. If there's a big difference in the before & after, likely that's the problem. Clogged cat will cause "no power".

It's a free test anyway. One of the guys here just went through the same situation.

 

[n8thgr8]

Cool, that'll be a good starting point thanks.
He wants me to come drive it to see if it's different than before.
I mean it's no Ferrari, but it's not completely inept in the power department.
I'll have him do a compression test to start

 

[Flyfish]

Cool, that'll be a good starting point thanks.

I'll have him do a compression test to start

And exhaust temp test.

 

[n8thgr8]

I'm on my way down there to check on them. He says it is idoling just fine, but when you mash on the gas there isn't any response.
Could this be a MAF issue too?

 

[listerdiesel]

I'd be looking at something simple first, like a throttle connection or MAF plug, that sort of thing.

Unless he is completely out of it as a mechanic, it's difficult to get it that wrong just by doing gaskets.

Peter

 

[n8thgr8]

He's a pretty good mechanic, lots of experience with import cars. He has done great work for me in the past.
I have been thinking of something simple. A MAF plug or something. I'll keep you posted as I find out info that might help.

 

[D Chapman]

Could have a plug wire on the wrong plug. A lot of times the truck will start and idle and you will not hear a miss until you hit the gas. It all goes to hell from there.

 

[p m]

Could have a plug wire on the wrong plug. A lot of times the truck will start and idle and you will not hear a miss until you hit the gas. It all goes to hell from there.

I was wondering why nobody mentioned that so far. A pair of misconnected ignition leads will let the truck start and idle, yet it'll do just that under load.

 

[listerdiesel]

I was wondering why nobody mentioned that so far. A pair of misconnected ignition leads will let the truck start and idle, yet it'll do just that under load.

I guess we all assumed the mech had that sorted out, it's not exactly rocket science is it?

I thought about it, but it's like all the 'silly' things, you have to start with the assumption that the assembly is basically correct.

Good call though.

Peter

 

[n8thgr8]

Well, I'm very thankful for all your suggestions. I've passed them along. My money is on the plug wire out of order. When I went to look I didn't check each wire for placement on the proper plug. I'll have to check that specifically next time. (Even though I asked "are the plug wires in the correct order? And I got a flat "yes")
Right now he is suggesting that I order a new MAF because that MIGHT be it.
I'm not going to order an expensive part and wait a week for it to get to Guam when you aren't sure. Test that sucker first.
And if I DO I'm gonna want the old one back too.
I'll keep you posted
Oh, any suggestions on how to test a MAF without swapping it out?

 

[Bosbefok]

Usually the plug wires are plugged into the wrong hole on the coils, easy mistake to make.
Unplug the MAF.

 

[p m]

Right now he is suggesting that I order a new MAF because that MIGHT be it.

If MAF was okay before the HG job, why would it go bad?

 

[n8thgr8]

If MAF was okay before the HG job, why would it go bad?

Exactly!

 

[ptschram]

Find a new wrench bender!

CEL on? Codes present?

 

[n8thgr8]

He says no codes are present.
Yah, this guy has done good work for me before, but I'm not happy about this situation. I'm usually the one to do the work, and I would have done the HG job myself, but I didn't want to be out of a truck for two weeks. Well, guess how long he's had it? close to three weeks.
I'm going to go down there on Saturday and inspect it myself and take it home no matter what. I'm done with this crap.

 

[KyleT]

Mis plugged injectors?

 

[ptschram]

It's not like a DI isn't a stupidly simple truck to work on.

 

[n8thgr8]

I KNOW right? If I can work on it than someone who makes a living working on European import cars should have no problem.

 

[Flyfish]

Make him check the exhaust (cats) for air flow!

Have him take an infrared heat gun and compare temps on the Y-pipe both before and after the cats. If there's a big difference in the before & after temps, likely that's the problem. Clogged cats WILL cause "no power" under load.

We had a guy who spent $$$$'s (yes, 4 $'s) doing engine work and everything under the sun with your same problem. After everyone was giving up all hope, a 2 minute, free test revealed a clogged cat.

Did I mention it's quick and free?