Blown77Z Posted August 16, 2008 Share Posted August 16, 2008 Yesterday while driving to work I was passing some "slow" driver on the highway when I noticed the power kind of die off. When I passed another "slow" driver a few seconds later I watched the RPMs this time and around 5k or so the car seems to hit a wall on power, or lack of power.... I played with it again this morning coming back home from work and around 5k or so under moderate throttle it seems fine, but under full throttle it seems to hit a wall. The car doesn't stumble or hesitate, but it does make a weird noise like it needs more fuel. Here's my observations on the issue: 1. Car doesn't pull after 5k under WOT, but makes a weird noise. 2. RPMs don't rise after 5k, needle just kind of stays there. 3. Fuel pump is kind of loud, but has been this way before. My initial and worst fear is the clutch is going out. But, the RPMs don't rise when this is happening.... My second thought was the FP, I checked it last night and under idle it's 58 PSI, I still need to check it under WOT, but don't have a gauge in the car yet. I'm starting to think it's fuel related. Either the injectors are dirty (never cleaned them) or the fuel filter is getting clogged. Any other suggestions? Quote Link to comment Share on other sites More sharing options...
mark Posted August 16, 2008 Share Posted August 16, 2008 Does it pop or back fire? Mine was doing something similar and it was a loose plug wire. I hope yours is that simple. Quote Link to comment Share on other sites More sharing options...
aziza z Posted August 16, 2008 Share Posted August 16, 2008 Sounds like a fuel issue. I would check fuel pressure at WOT first. Could just be a bad pump. What pump are you using? Quote Link to comment Share on other sites More sharing options...
Blown77Z Posted August 16, 2008 Author Share Posted August 16, 2008 Mark, I just checked on the plug wires and the plug wire on Cylinder 3 was loose !!! I will test it in about an hour or so when I drive it to work. Aziza, I'm using the in-line pump from JCI. I will check the FP gauge under the hood while I'm revving the engine to see if it drops under WOT if the "loose wire fix" don't work... Keep the suggestions coming guys ! Thanks, Tim Quote Link to comment Share on other sites More sharing options...
mark Posted August 17, 2008 Share Posted August 17, 2008 I hope that's all it was. Quote Link to comment Share on other sites More sharing options...
Blown77Z Posted August 17, 2008 Author Share Posted August 17, 2008 It's a fuel related issue. Under WOT my FP drops to around 20 PSI I'm going to check the fuel pump relay first. Not sure why I didn't think of this before, but for the past few weeks the relay won't kick on the first time the key is turned over making me have to play with it a little to make it work. I think it might be a loose connection on the relay itself. Next, I'll check to see if voltage to the fuel pump drops when I give it gas. Off for diagnoses... Quote Link to comment Share on other sites More sharing options...
Blown77Z Posted August 18, 2008 Author Share Posted August 18, 2008 I believe the fuel pump relay is fine. I didn't see a voltage drop from the power wire leading to the pump when I gave it gas. Next step I'll check the filter before the fuel pump. BTW, I noticed today after driving the car to work the fuel pressure was reading about 5-7 PSI lower at idle than normal (58 psi). Could this be a sign of the fuel pump failing? Quote Link to comment Share on other sites More sharing options...
Savage42 Posted August 18, 2008 Share Posted August 18, 2008 Could be pump or the filter has some fine dirt in there and is restricting flow. Been there, done that. Quote Link to comment Share on other sites More sharing options...
Blown77Z Posted August 18, 2008 Author Share Posted August 18, 2008 Aziza, I found your thread you made regarding your fuel pump issues; http://forums.hybridz.org/showthread.php?t=135835&highlight=bad+regulator How did you resolve your issue? Quote Link to comment Share on other sites More sharing options...
aziza z Posted August 18, 2008 Share Posted August 18, 2008 Yea I did figure out. For me it was a couple of factors. 1- The "new" fuel pump was no good. Brand new and only lasted 6 monthes 2- There was a voltage drop at the pump 3- Im using an ls1 gas tank. Turns out theres a built in regulator thats intank that needed to be removed. After addressing all of these issues the problem it gone and the power is back. I now have a fuel pressure and A/F gauge in the car. Quote Link to comment Share on other sites More sharing options...
Blown77Z Posted August 18, 2008 Author Share Posted August 18, 2008 Aziza, did you test for voltage on the pump terminals themselves? Your readings were in the 11.0 - 11.5v range correct? And my fuel pump from JCI is not that old either, been running it for about 5 months now... Quote Link to comment Share on other sites More sharing options...
aziza z Posted August 18, 2008 Share Posted August 18, 2008 Aziza, did you test for voltage on the pump terminals themselves? Your readings were in the 11.0 - 11.5v range correct? And my fuel pump from JCI is not that old either, been running it for about 5 months now... Yes i was testing them there. They should be in the 13-14v range. Thats where its at now. Quote Link to comment Share on other sites More sharing options...
Phantom Posted August 18, 2008 Share Posted August 18, 2008 Be sure you check your fuel filter and also the strainer at your tank exit before going hard after the fuel pump. Quote Link to comment Share on other sites More sharing options...
hoov100 Posted August 18, 2008 Share Posted August 18, 2008 check you coil packs as they might be dieing and check voltage to the coil packs. Quote Link to comment Share on other sites More sharing options...
Blown77Z Posted August 19, 2008 Author Share Posted August 19, 2008 I installed new power and ground wires for the fuel pump yesterday and tested voltage again. Voltage ranged from 11.4 - 11.9v on idle and dropped to almost 10v on WOT ! So I believe there's something in the wiring, maybe the relay itself? Going to check the filter later on today. BTW, I forgot to mention the needle on the FP gauge attached to the regulator bounces back and forth between 58-56 psi really fast on idle..... Quote Link to comment Share on other sites More sharing options...
Phantom Posted August 19, 2008 Share Posted August 19, 2008 You have confirmed that you have a full 14.4 volts at the battery? Those readings indicate you could have a dead cell. Quote Link to comment Share on other sites More sharing options...
Blown77Z Posted August 19, 2008 Author Share Posted August 19, 2008 EDIT, I just ran another test just now and here's the results. Battery is at 13.4v Tested at the fuel pump terminal: Fuel pump voltage is 12.4v-12.6v at IDLE Fuel pump voltage is 12.1v.12.2v at WOT You really think it's a dead cell in the battery ? Quote Link to comment Share on other sites More sharing options...
Phantom Posted August 19, 2008 Share Posted August 19, 2008 Need to check the battery when the engine is not running. It would be better to pull it and take it to a parts place that can load check it. A good 12 volt battery should have 14.4 volts. At 13.5 you may have a weak cell. Quote Link to comment Share on other sites More sharing options...
Blown77Z Posted August 19, 2008 Author Share Posted August 19, 2008 The voltage at the battery when the car is off is 12.5v......... Now, where's my receipt for it, hehe. Quote Link to comment Share on other sites More sharing options...
MikeJTR Posted August 19, 2008 Share Posted August 19, 2008 I once had a similar problem on an engine swap, in which the engine quit making power at wot above a certain rpm. It turned out that the air-intake ducting was collapsing between the filter and the throttle body, acting as a choke. After looking at your photo gallery, I can tell you that the accordian looking intake connector was the same type of connector that caused the problem on my application. The weird noise you hear is the air running past the collapsed section of the intake. Quote Link to comment Share on other sites More sharing options...
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