Printable View
'86 2WD, manual
Major loss of power going up hills. I used to be able to go 60mph up a decent hill in 4th gear, now I can barely go 35 in 3rd gear.
Things I have replaced and checked:
Cap and rotor
Spark plug wires
Timing adjusted
Checked for air leaks
No error codes showing
Fuel filter was replaced about 2 years ago, 10k miles
Any ideas or suggestions would be appreciated. Thanks
#1 thing to do is make sure there's oil in the crank case. I know it sounds stupid, but there was actually somebody here a while back with this same problem, and I took for granted he'd checked this (he hadn't). He even took it to his mechanic who also neglected to check the oil. Well, he was out of oil and kept driving until he destroyed the engine. In his last post he seemed a bit bitter that nobody on the forum pointed that out before he ruined the engine :dizzy:.
There are other things it could be, but most likely would be the catalytic converter. Check the EGR modulator for damage. If it shows heat damage, then it's very likely the cat is plugged up. Inside the cat there is a mesh/grate that the exhaust must flow through. If the van has been run for long term with any of it's ECU sensors failed or disconnected your cat will eventually plug up. The only way to be sure it's not plugged is to remove it and hold it up to a light. If it's clear you should be able to see through the mesh inside. Hopefully the bolts aren't too rusty and it will come off. Be sure to use WD-40 or equivalent on the bolt threads before trying to remove.
Good luck and let us know what you find. Tim
It was running for a while with a code for failed O2 sensor and I replaced that, maybe a bad 02 sensor could have fouled it up?Quote:
Originally Posted by timsrv
If it does need a new cat converter, wheres the best place to buy one?
Thanks Tm
Depends on how long "a while" is. If you do determine it's the cat, and the rest of your exhaust system is still in good shape, then I would probably get a "direct fit" type bolt on cat from a place like RockAuto.com. As long as you're not in CA or New York you can get one shipped for ~$100. If the rest of your exhaust system is falling apart anyhow, then I'd take the thing down to an exhaust shop and have them do a "cat back replacement" (including the cat). They would likely use a cheaper "weld on" universal cat and replace everything from that point back. I've been able to find good exhaust shops in every city I've lived in. The good shops can replace your system for a very reasonable price. I'm thinking ~$300 for cat back replacement.
But just keep in mind there are other things that can cause your power issue (your cat could be fine). I don't like to condemn cats without removal and inspection, but before removal, I'll usually have somebody revving the engine while I'm checking force/flow from the tail pipe. Assuming the rest of the sytem is sealed, you should get good blasts of exhaust when the engine is revved. If the cat isn't completely plugged, this is more of a gut feel test and can only indicate failure. If you find a melted EGR modulator, then it's almost certainly a failed (plugged) cat. Tim
Had to grind off the old bolts and finally got the new one bolted on. Unfortunately there is a lot of exhaust leaking from the top and bottom areas of the flange in between the cat and muffler. I am using a new gasket that came with the cat.Quote:
Originally Posted by timsrv
Any ideas on how to fix the exhaust leak between the flange? I cleaned it up as best I could with a dremel before installing it
"Direct fit" sometimes leaves a bit to be desired. I've dealt with this before. Sometimes double gaskets will work. Sometimes using the high temp silicone in conjunction with an extra gasket will help. Good luck. Tim
Thanks I will try that.Quote:
Originally Posted by timsrv
The new cat convertor didn't help the problem. Can you suggest a next step on what I can try for the issues described above?
How about simple stuff like checking the air filter? (didn't see that on your list). Intake air restriction can be just as bad as exhaust restriction. If it's been 2 years since replacing fuel filter, it's unlikely, but still possible it's plugging up and restricting fuel flow. I also did not see spark plugs on your list. I'm assuming you replaced them with the wires, but just making sure. How did you check for vacuum leaks? You said there were no codes, but did you actually check them by jumping your "check engine connector"? If not you should do that. You should also check your timing advance. Use a timing light to verify timing with your check engine connector jumped and then again without. There should be a noticeable difference when the jumper is removed. If advance is not working, this would indicate a faulty TPS. You should also test the diaphragms on your EGR modulator and the EGR valve. Use a piece of vacuum hose and make suction with a mitivac or your mouth to verify they both hold a vacuum.
Sorry if you needlessly replaced the cat. I was hoping you'd report back with test/inspection results before doing that. Tim
PS: There's also possible drag issues like brakes hanging-up, but those will usually make themselves obvious with smoke and/or stink.
How about simple stuff like checking the air filter?Quote:
Originally Posted by timsrv
Changed the air filter a couple weeks ago
If it's been 2 years since replacing fuel filter
Changed it today and didn't notice a difference
did not see spark plugs
Those were changed
You said there were no codes
I jumped the wire and got the regular flashing no code signal
You should also check your timing advance. Use a timing light to verify timing
Was working with a mechanic friend and they used a timing light and made an adjustment based on some info they found (with and without wire jumped), it didn't make a difference. I don't remember if he noticed a difference with and without the jumper
test the diaphragms on your EGR modulator and the EGR valve
I still need to test this. Will be looking into the process
PS: There's also possible drag issues like brakes hanging-u
I don't think it is this as it has been going on for months and it has no issues going 60+ mph on flat ground It' just when I hit hills it starts to lose power.
There is a slight stuttering or jolt in power at random times, very subtle and not that often, both on flat and hills. Don't know if that's directly related
I was having power loss going up hills in my 85 2wd LE. It got progressively worse and then started sputtering and misfiring. When I pulled my spark plugs (that I changed 1 year ago), I found one that was extremely clean. After checking everything that you did plus some, I decided that my cylinder 2 injector was clogged. So after ripping the whole intake off, removing the fuel rail, and removing the fuel injectors, I took them into Dr. Injector to have them tested, cleaned, and retested. #2 cylinder's fuel injector was only spraying 15% of what it should. The others were at 85%.
Maybe, if you have exhausted everything else including a compression test, you have a clogged injector.
Not to hijack or anything, but since it was mentioned...Tim, how much should the EGR diaphragm move when suction is applied? Mine moves, but it is a very slight movement.
Plugged injectors can definitely create power problems, but in my experience, the power issue doesn't get really bad until one plugs up almost completely. At that point, the van will miss at an idle (which AnotherUser didn't report). However, it's a good observation and worth looking into. AnotherUser, it's probably a good idea to check for a non-firing cylinder. It's easy to figure out by pulling plug wires one at a time. If you pull a wire and the van stumbles and/or stalls, then that cylinder was firing (good). If you pull a plug wire and there is no change, then that cylinder wasn't firing (bad). Since electronic issues are more common, and because it's such a PITA to pull injectors, I recommend swapping the plug, distributor cap, and that plug wire before ripping into the injectors. If that doesn't remedy, then I'd start digging into the injectors. If you determine it's #1 or #2, you can check those injector connectors without getting too carried away, but if they check out fine, then you'll need to start wrenching.
When I had this problem, after identifying which cylinder wasn't firing (#3 in my case), I removed that plug and put my camera probe down the hole. While viewing my monitor I jumped the "fuel pump check connector", turned the key to "run", then identified #3 injector wires in my harness, then put power to them. The injector clicked, but no fuel sprayed. To verify what a working injector looked like, I tried it again on #1 and noted fuel spray/mist entering the cylinder (these bore scope cameras are awesome). My way is more positive and is certainly a more direct to verify, but it requires the use of special equipment. With the way described in the previous paragraph, you can swap out with used items for testing and it won't cost you anything but time. Another advantage I have (that you most likely don't) is I build my own injector wire harnesses. Having an additional separation point allows me to quickly identify individual injector circuits and allows me to apply power to activate each one easily (without cutting or poking holes in wires). Good luck and keep us updated on what you find. Tim
Have you checked compression?