Low power?
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Laughing Gas
Joined: Sep 2004
Posts: 1,057
Likes: 3
From: gravel road ONTARIO
Low power?
Monday I took my Aerostar into a trusted tranny place for (I'm a truck/coach mechanic) service/inspection/adjustments. The guy incharge took it for a roadtest and said everything was working fine and I should wait to get it serviced until after I fix the "low power problem". I had thought it was a problem with the trans. It gets into just a small grade and it slows down drastically and won't downshift until you floor it. It just past a dyno etest and was very clean on emmissions output. I checked plugs/wires, and they are very clean. Air filter looks fine, I just put on a new fuel filter. What should fuel pressures be and when?
It is a 1993 3.0 A4LD and has the 3.73 ratio 7.5" axle, Could a vacuum leak cause low fuel pressures? Sorry some of these questions may sound dumb but I've been fixing Diesels for years and have lost all my Gas brains!
Thanks For all the help!
It is a 1993 3.0 A4LD and has the 3.73 ratio 7.5" axle, Could a vacuum leak cause low fuel pressures? Sorry some of these questions may sound dumb but I've been fixing Diesels for years and have lost all my Gas brains!
Thanks For all the help!
Answers
Post Fiend
Joined: Apr 2005
Posts: 5,720
Likes: 5
From: Washington state
pull ECU codes and please post to forum....some codes do not set a CEL
what is your gas mileage? indicates engine efficiency....
what is condition of ATF and how many miles since changed? how old is vacuum modulator on tranny? check for ATF dripping out of vacuum line on vac. mod.....is there full vacuum applied to vac. mod? any breaks, kinks, leaks or closures in vac. line to mod.?
the torque converter lockup and 3-4 upshift/downshift are controlled by the ECU....can be affected by failing throttle position sensor, failing O2 sensor, failing ECT, IAT or contaminated MAF
when was MAF and O2 sensors last serviced/changed? both have a major effect on engine power/mileage...clean emissions test does not list engine horsepower peak....
what is your gas mileage? indicates engine efficiency....
what is condition of ATF and how many miles since changed? how old is vacuum modulator on tranny? check for ATF dripping out of vacuum line on vac. mod.....is there full vacuum applied to vac. mod? any breaks, kinks, leaks or closures in vac. line to mod.?
the torque converter lockup and 3-4 upshift/downshift are controlled by the ECU....can be affected by failing throttle position sensor, failing O2 sensor, failing ECT, IAT or contaminated MAF
when was MAF and O2 sensors last serviced/changed? both have a major effect on engine power/mileage...clean emissions test does not list engine horsepower peak....
Post Fiend
Joined: Oct 2005
Posts: 5,242
Likes: 0
From: Kiev, Ukraine
Theoretically vacuum leak may cause low fuel pressures, but if I have vacuum leak, I heve fast idle! Try to disconnect vacc.hose from the fuel regulator and check pressure again!
If fuel pressure is not good ore increases ufter key on slow, check fuel filters (one is under the van, the other is in the tank), and check fuel pump!
If fuel pressure is OK, try to read OBD-II data at idle and 3000 RPM... and let me see results. I can see what is going on! May be MAF, may be O2 may be clogged cat.....
If fuel pressure is not good ore increases ufter key on slow, check fuel filters (one is under the van, the other is in the tank), and check fuel pump!
If fuel pressure is OK, try to read OBD-II data at idle and 3000 RPM... and let me see results. I can see what is going on! May be MAF, may be O2 may be clogged cat.....
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