Carus Posted September 29, 2009 Share Posted September 29, 2009 I have owned my 94 LS400 for a year now. It has recently developed a few problems that are giving the mechanics in my town a fit. First it started as my car not being able to get past 2k RPM's sometimes as in if giving it enough gas from a dead stop to make a turn into traffic, so not much at all, and if going down the road at any speed and laying on the accelerator to gain some fast speed i.e. to pass somebody, at this time the TRAC light and check engine light come on . Second after the car has been driven and gets up to it operating heat my acceleration from a dead stop takes a good 15-20 seconds before it really speeds up past 5-10 mph. I have only one mechanic in my area to try before I break down and take it to the closest dealership that is 2 hours away. I you Guys have any ideas please help. If given any advice I would greatly appreciate it. Quote Link to comment Share on other sites More sharing options...
curiousB Posted September 29, 2009 Share Posted September 29, 2009 Is check engine light on? Could be fuel pump or fuel filter starving car for fuel. Could be fuel injection system has dropped into limp mode due to a sensor failure such as MAF, throttle position, coolant temp sensor, O2 sensor.... Could be ignition problem where spark dies at 2k indicating problem coil(s) Could be temperature coolant sensor telling ECU engine is cold when it isn't Hard to tell from your info. Can you read any codes stored in the ECU to get an idea of where to start? Can you put a fuel pressure gauge on fuel manifold and read pressure when its running poorly (to see if fuel pressure too low)? Quote Link to comment Share on other sites More sharing options...
Carus Posted September 29, 2009 Author Share Posted September 29, 2009 Is check engine light on?Could be fuel pump or fuel filter starving car for fuel. Could be fuel injection system has dropped into limp mode due to a sensor failure such as MAF, throttle position, coolant temp sensor, O2 sensor.... Could be ignition problem where spark dies at 2k indicating problem coil(s) Could be temperature coolant sensor telling ECU engine is cold when it isn't Hard to tell from your info. Can you read any codes stored in the ECU to get an idea of where to start? Can you put a fuel pressure gauge on fuel manifold and read pressure when its running poorly (to see if fuel pressure too low)? I don't have any equipment do read codes that is a soon to be bought item. I have had the plugs and wires replaced. Have been planning on replace fuel pump and filter soon the car sat in an impound lot for 2 years. Also I have had the temperature coolant system worked on in the last couple of week the coolant pump was also replaced. when I bought the car I had the timing belt replaced. does that help some Quote Link to comment Share on other sites More sharing options...
curiousB Posted September 29, 2009 Share Posted September 29, 2009 I don't have any equipment do read codes that is a soon to be bought item. I have had the plugs and wires replaced. Have been planning on replace fuel pump and filter soon the car sat in an impound lot for 2 years. Also I have had the temperature coolant system worked on in the last couple of week the coolant pump was also replaced. when I bought the car I had the timing belt replaced. does that help some Well I'd get a code reader or go to an auto store that will do it for free for you. That info could be helpful. Some older models allow you to get codes with just a piece of wire and they are displayed in the dashboard message centre. I wouldn't run out and change fuel pump and filter just because. I'd go buy a fuel pressure gauge from Harbor Freight tools for $10 and measure pressure. For $10 tool you may find $200 fuel pump is ok. If car was sitting that long maybe the injectors are dirty. Perhaps some injector cleaner fluid in next few tanks of gas might clean those out. . Quote Link to comment Share on other sites More sharing options...
Carus Posted September 29, 2009 Author Share Posted September 29, 2009 I don't have any equipment do read codes that is a soon to be bought item. I have had the plugs and wires replaced. Have been planning on replace fuel pump and filter soon the car sat in an impound lot for 2 years. Also I have had the temperature coolant system worked on in the last couple of week the coolant pump was also replaced. when I bought the car I had the timing belt replaced. does that help some Well I'd get a code reader or go to an auto store that will do it for free for you. That info could be helpful. Some older models allow you to get codes with just a piece of wire and they are displayed in the dashboard message centre. I wouldn't run out and change fuel pump and filter just because. I'd go buy a fuel pressure gauge from Harbor Freight tools for $10 and measure pressure. For $10 tool you may find $200 fuel pump is ok. If car was sitting that long maybe the injectors are dirty. Perhaps some injector cleaner fluid in next few tanks of gas might clean those out. . Thank you for your advice I will most definitely try what you suggested before I decide to put it back in shop Quote Link to comment Share on other sites More sharing options...
SRK Posted September 30, 2009 Share Posted September 30, 2009 If the engine lacks power and remains smooth, then it is not injectors, or plugs, or wires. Eight individual parts don't fail at the same time. You may have a blocked catalytic convertor. Check by holding rag over both tailpipes as someone revs the engine. If you don't get a big rush of exhaust, that's the trouble. It's also possible that whoever replaced the timing belt got it installed a tooth or two off the correct marks, or it has jumped time. Don't buy parts. Diagnose the thing first. Quote Link to comment Share on other sites More sharing options...
Carus Posted September 30, 2009 Author Share Posted September 30, 2009 If the engine lacks power and remains smooth, then it is not injectors, or plugs, or wires. Eight individual parts don't fail at the same time.You may have a blocked catalytic convertor. Check by holding rag over both tailpipes as someone revs the engine. If you don't get a big rush of exhaust, that's the trouble. It's also possible that whoever replaced the timing belt got it installed a tooth or two off the correct marks, or it has jumped time. Don't buy parts. Diagnose the thing first. Thank you I will also check this out asap. Quote Link to comment Share on other sites More sharing options...
billydpowell Posted September 30, 2009 Share Posted September 30, 2009 Follow their leads, they know what they are talking about.. check the convertors first, it's simple.. Quote Link to comment Share on other sites More sharing options...
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