Loss of power after 1000 rpm.

[talonx]

I posted last week on how my wire harness melted and the Blazer died.
Well, I respliced 60 of the 65 wires going to the PCM. (solder splices then shrink wrap)

After replacing a few fuses the Blazer starts up/runs fine.
I took it out for a test cruise and at about 1000 RPM it bogs/loses power
and wont go. If you give it more gas it wont rev higher(bogs) or go faster.
I can take it easy and get to 20 mph. I can feel it shift to second.
Same thing in reverse. If I put the Automatic trans in 1st and leave
it there it does the same thing.

In park it revs up smooth and idles great.

I'm thnking the PCM may be blown and the engine won't
run right under load? Does that make sense?

The check engine light has not come on. It does come on with the other
dash lights when you turn on the ignition.

[talonx]

oh, 1999, 2 dr, 4.3 L Auto.

This morning to asses the ECM I disconnected
the cam position sensor. No check engine light when started.

I disconnected the MAF sensor. The SES light did come on.

I still think the PCM may not be adjusting the engine right.
IS there something in the trany? But, when I leave it in 1st
or reverse I get the same problem. Bogs down and wont rev past
1000/1500 rpm.

I'm going to take out the ECM and see if anything visually blew on the
board.

I there anything else I should be looking for?

[talonx]

Well, the PCM looks well like a PCM. No visible damage.
I'm going to check with the dealer and see if they can test it.
Another test I did was rev the engine up in drive with the brakes on. Even not moving the same thing happend @ about 1500/2000 rpm.
The engine would not rev up.

Would a clogged catalytic do this? Idle and rev fine in park, but not run in drive?

[rlith]

Well the fact that it runs would indicate the ecm/pcm is fine... Yes, start looking to the cat, vac hoses and sensors...(just because a sensor is bad doesn't mean it will set an SES) Also check the resistance on all the splices you did... Too much or too little can cause the same issues.

[talonx]

I checked the TPS and my splices. Looks O.K.
In Drive, its like the engine wants to go, there's
surging around 1500 rpm. Like it almost wants to kick in.

The exhaust smells odd, it also stings your eyes.(too rich?)
Maybe more condensation than usual.
The Cat bols are a pain. I need to borrow an impact wrench.

I disconnected the pass side air injection and there seemed to be
more power when I drove it.

Can catalytic converters clog pretty quick?
I guess I mean go from running to not?

[BlazerLT]

Aso clean your MAF sensor by spraying TB cleaner or brake cleanetr through it to get rid of the black gunk on the internal sensor wires.

[talonx]

Thanks for all the help.
It was the Catalytic converter (rear) the inside was clogged/shattered.
$180 for an aftermarker, the dealer wanted $850
and I/m pretty sure they were going to get the one I bought from the local parts store.

I never would have thought that the cat could go so quickly like that!

[rlith]

$180??? Wow, I paid 80 for my high flow Catco from summit

[BlazerLT]

Originally Posted by rlith

$180??? Wow, I paid 80 for my high flow Catco from summit

180 is probably the price installed.

I paid $300 installed for mine in Canada.