Dalee1104 Posted April 3, 2017 Share Posted April 3, 2017 Okay so the damn issue is back now. Right around 2.5k rpms I have absolutely no power. The car just climbs so damn slowly, feels like I go from a 160hp car to a 90hp car. But then it disappears after about 4 or so. That gap takes absolutely forever to clear. For awhile I thought it was the gas I was using so I started using premium and it seemed to go away, power was there through and through. Now it's back yet I'm still using premium. The engine has just been gone through and cleaned very thoroughly and everything is in very good shape so I'm unsure of what it is, any idea? Link to comment Share on other sites More sharing options...
Setnev Posted April 3, 2017 Share Posted April 3, 2017 More information is needed. Any codes? Does it bog down like a lack of fuel? Conditions that it happens? Any recent additions to the engine in terms of sensors, maintenance items, etc. Link to comment Share on other sites More sharing options...
Dalee1104 Posted April 3, 2017 Author Share Posted April 3, 2017 No engine codes but I'm not really sure what lack of fuel bogging feels like? We checked the fuel pressure and it's in the good range. I don't know if this could be anything but it looks like it's only starting to happen when it's warm outside, had the same issue last summer but only in the summer. There hasn't been any additione to the engines and the sensors are all okay with no cel but I do think my O2 sensors need replaced as I'm running very rich. Lots of unburned fuel. But even then I still never had this issue until now and last summer Link to comment Share on other sites More sharing options...
Dalee1104 Posted April 4, 2017 Author Share Posted April 4, 2017 It seems more prominent in 3rd and 4th gear if that makes any difference. Light throttle is the worst Link to comment Share on other sites More sharing options...
choover1101 Posted April 4, 2017 Share Posted April 4, 2017 Catalytic converters clogged? Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Dalee1104 Posted April 4, 2017 Author Share Posted April 4, 2017 Just got a brand new high flow cat welded in with the new exhaust system about a month ago so I don't think it would be the cat. Car acted a little weird this morning as well. Went to start it and it held the rpms at about 2.5k then randomly dropped down. It never revs that high on a start. Not sure if those are connected? Link to comment Share on other sites More sharing options...
Setnev Posted April 4, 2017 Share Posted April 4, 2017 Let's start with the basics that control the AFR. 1.) Check the air filter, you should be able to see light through it. If its clouded or hard to see light, replace it. 2.) Clean the MAF. The MAF is a wire resister that measure the amount of voltage drop as the wires cool from air passing through them. The ECU determines how much air is going in and adjusts the fuel injectors to provide more or less fuel depending on engine load 3.) Check the IACV to see if it's dirty. IACV will cause erratic idle, both high and low. 4.) Check the fuel injectors to if they may be clogged. Clogged injectors will cause an uneven fuel spray and could cause it to lean out the AFR 5.) Ensure you fuel pressure regulator is working properly. You said you've tested fuel pressure and it's good, the pressure regulator runs off of vacuum. Check the vacuum line to the fuel pressure regulator on the front of the rail. If you're getting a prolonged rich burn condition, the spark plugs will be blackened with soot deposits on them. An overly lean condition will show scorching on the plugs. 6.) Do an "at fault" spark plug reading. This is a test that is pretty easy. Take the car out on a test drive. Drive it until it exhibits the type of failure you're experiencing. When the fault happens, turn the key back 1 click to the ACC position (not off) to kill the engine and pull off to the side of the road. Remove the most accessible spark plug and see what kind of fouling it has. Refer to this link for readings. There's also a lot of valuable information on that site that tells you how determine the proper diagnosis of other issues based on the spark plugs alone. 6.) Check your timing. Are you sure the belt didn't jump a tooth? It's not hard to take the front plastics off to check the timing. It may not make a difference at idle or before you get to the power band, but one tooth will cause WOT and cruising RPM's to feel like there is no power. Link to comment Share on other sites More sharing options...
doublechaz Posted April 4, 2017 Share Posted April 4, 2017 +1 to setnev. When mine was jumped 2 teeth on the left cam, it would idle rough and misfire. Anything above idle RPM was completely fine (except rich as he11) at moderate throttle up to 3750 RPM which would shut off fuel completely. Also, WOT mid RPM was about 25 HP rather than the 80ish HP of moderate throttle. Timing belt problems can be pretty weird and the only sure way to know is to pull those covers and verify the marks. Also, watch out, there is a set of marks for timing, and there is a different set of marks used for assembly to keep the valves from getting intimate with the pistons. Your service book should say which is which. I'm at work and don't want to mis-remember which is which. Link to comment Share on other sites More sharing options...
Dalee1104 Posted April 5, 2017 Author Share Posted April 5, 2017 So most if that is actually things I just went through. Air filter is new, iacv isn't the best but was cleaned and taken care of, fuel injectors very clean and in shape (had a shop run a acid flush like thing), timing was done after the engine got dropped in the car, it was messed up so we did it again so everything should be spot on there. What about the fuel pressure regulator going bad? The vacuum fittings are all new but I'd imagine this fuel pressure regulator is about 20 years old. Only thing left on this car that I havent done is O2 sensors, a couple misc. sensors, and the rest just re cleaned and reused all the other bits I'm gonna clean some things and check on them, just not sure what this rich fuel mixture is from, possibly the pressure regulator? Link to comment Share on other sites More sharing options...
doublechaz Posted April 5, 2017 Share Posted April 5, 2017 Possibly. With high vacuum it should be about 30psi fuel pressure. Without vacuum like at WOT it should be about 38 psi. If it's sending 38psi all the time it would be crazy rich. With the jumped timing belt, mine was also super rich because the conflicting timing signals from the cam and crank sensors made the ECU double fire two of the injectors, or else at the high end it would never fire two of them. That was fun to watch on the oscilloscope. Link to comment Share on other sites More sharing options...
Dalee1104 Posted April 15, 2017 Author Share Posted April 15, 2017 Update for anybody paying attention still. I dropped 180 on new O2 sensors, one front and rear. That was all of my issues, car feels back to its normal self again. Yes they are expensive but do not skip out on O2 sensors Link to comment Share on other sites More sharing options...
doublechaz Posted April 15, 2017 Share Posted April 15, 2017 +1. Only the good O2 sensors. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.