1989 power loss

[sgttim38]

Hello all this is my first post so forgive me if it's already been discussed. I have a 1989 Comanche Eliminator with approx 230K miles. It leaks oil but was running like a champ. A few days ago I was traveling down the road and truck started losing power. I had to turn around and get it back to the house, When I was able to pull into the driveway the truck would barely pull itself. It went form running great to backfiring and sputtering. Backfire sounded as if it was coming through the air filter. If the truck is at idle it still runs ok but but when I put it in gear the rpm's drop and starts missing again. I've changed the fuel filter and repaired a broken vacuum line that I wasn't aware. Now the truck is running better but still won't pull itself. I don't know if it possibly the catalytic converter or if a sensor is bad. Has anyone experienced this before and if so what was the fix. Thanks

[Burke]

My first post too, you NEED to start here : http://comancheclub.com/topic/36382-cruisers-renix-tips/

 

Don't worry about #2 or #27 they don't apply to 89's, however #1 through #6 are fundamental to all the sensor testing, if you don't do them - and just skip ahead, you'll waste time & probably money.

 

Beyond that I can't offer much more, but others will.

 

 

Burke

[Knucklehead97]

Which vacuum line was it that was broken?

[HOrnbrod]

Could be many things, but the first thing I'd do is check your fuel pressure at the rail Schrader valve with a fuel pressure gauge. Should be 31psi / 39psi w. and w/o the vacuum line on the regulator. You can rent a gauge at Autozone or similar if you don't have one.

[sgttim38]

Sorry Knucklehead I'm not sure which vacuum line it was. The break was located near the air intake and ran to a connection near the front of the motor. There are 4 connections at the point. Only three of the connections actually have vacuum lines attached. I used to have a chilton's manual years ago when I owned my first comanche but included it when I sold that truck. 

Thanks guys

[Knucklehead97]

Not really sure which vacuum line that is. But any leak is bad. Check your MAP vacuum line. It runs off the side of your throttle body to a sensor on the firewall. Its one of the most important vacuum lines and personally mine has melted itself shut and given me NO power but a perfectly fine idle...

[1989 Eliminator]

Ive done a BUNCH of work... basically everything from cruiser tips to looking into the wiring harness to fine my issue. You can find the link in my signature for low/rough idle. Its a long forum but a lot of information.