Fuel pump/pressure/starting issues
Fuel pump/pressure/starting issues I've been having idle issues where the car would surge usually when I put it in drive or reverse. Sometimes low enough to kill the motor. Finally got a mech fuel pressure guage and everything looked OK (40-42 primed, 32-35 idle). FPR seems to be doing it's job too. The fuel pump started getting louder and sounding different, then it crapped out yesterday morning. Luckily, I was able to pull the pump out of my parts car and install it in my car same day. Car still starts and idles the same as before. I put the guage on it after the pump swap and it takes about 3 turns of the key (on/off) to prime it up to 42psi. The first prime will get me up to about 25-30, next one close to 40, and 3rd one up to 42. But when I start the car it usually turns over for a few seconds before it fires and it stumbles a little before it starts running normal. Then once I put it in R or D, the RPMs drop real low and sometimes it will surge for a while until it levels out. As long as I keep the car in D it will idle good from there. At red lights, it idles right at 700 nice and smooth.
My main question is: Should the fuel pressure shoot up to 42psi right when I turn the key to prime it, or is it normal climb slow and have to do it a few times before it gets to 42? What else could be causing hard start and surging?
I'm planning on ordering the 255 Walbro if it's what everyone recommends. Will that change fuel pressure at all or help my situation any?
My main question is: Should the fuel pressure shoot up to 42psi right when I turn the key to prime it, or is it normal climb slow and have to do it a few times before it gets to 42? What else could be causing hard start and surging?
I'm planning on ordering the 255 Walbro if it's what everyone recommends. Will that change fuel pressure at all or help my situation any?
Launching!
Joined: Oct 2010
Posts: 298
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With my stock pump ig goes to 42 in just the first prime (2-3 second key ON). is the pump you installed really good? Did you check the fuel pressure while the car is running(idle)? What with the fuel filter did u replace it ? try remove the fuel line from the fuel rail and let a friend put the key ON and see if it take long for the fuel to puor out, or it sputters when comming out.
All that is if the problem is fuel related
All that is if the problem is fuel related
Fuel pressure is good when running, builds up as throttle goes up, and gets up to 42/43 at WOT. The fuel pump swap is intended to be temporary until I can get a new one. I didn't want to buy the Autozone brand, so I have to order one online and wait. This is my only vehicle at the moment so I had to get it running ASAP.
That's what I'm trying to figure out...if the start/surge problems are fuel related. I figured it should go up to 42 on the first prime, but it doesn't so that tells me somethings wrong. I pulled the fuel filter and it looks great, flowing great. I haven't disconnected by the fuel rail yet.
Also, I can tell you that when I disconnected the line at the pump to replace the pump, it had a lot of pressure built up and fuel sprayed everywhere.
That's what I'm trying to figure out...if the start/surge problems are fuel related. I figured it should go up to 42 on the first prime, but it doesn't so that tells me somethings wrong. I pulled the fuel filter and it looks great, flowing great. I haven't disconnected by the fuel rail yet.
Also, I can tell you that when I disconnected the line at the pump to replace the pump, it had a lot of pressure built up and fuel sprayed everywhere.
I just wanted to follow up on this thread for anyone searching this forum in the future with similar issues. I've made some progress, but still having issues.
I installed a new FPR. The fuel pressure jumps up to 40-42 on 1st prime now, so I'm convinced the FPR was bad. I'm still waiting on my racetronix fuel pump and harness, but the temp fuel pump seems to be working good. Won't know how good until I get the new stuff installed. I will update when I do.
Then, a few days later, the opti started giving me problems (I kinda knew it was coming). SES light came on and codes were hi-res and low-res opti codes. I had a brand new Chandler opti on stand by, so I got it installed. Car is running a lot better overall, but starting still takes a couple seconds usually. The surging issue is almost non-existent, but still a little surge when shifting into R or D, from P or N.
I think the opti had a lot to do with the surging issue and the FPR had something to do with the starting issue. I'll see what happens with the new pump and go from there. I've only started the car a handful of times since the opti replacement, so the pcm may be still trying to learn it's sweet spot when starting and idling.
I installed a new FPR. The fuel pressure jumps up to 40-42 on 1st prime now, so I'm convinced the FPR was bad. I'm still waiting on my racetronix fuel pump and harness, but the temp fuel pump seems to be working good. Won't know how good until I get the new stuff installed. I will update when I do.
Then, a few days later, the opti started giving me problems (I kinda knew it was coming). SES light came on and codes were hi-res and low-res opti codes. I had a brand new Chandler opti on stand by, so I got it installed. Car is running a lot better overall, but starting still takes a couple seconds usually. The surging issue is almost non-existent, but still a little surge when shifting into R or D, from P or N.
I think the opti had a lot to do with the surging issue and the FPR had something to do with the starting issue. I'll see what happens with the new pump and go from there. I've only started the car a handful of times since the opti replacement, so the pcm may be still trying to learn it's sweet spot when starting and idling.
Great to see we could get you back on the road. As far the the fuel pump, are you sure you're running an authentic unit? When we researched getting into FPs, we saw counterfeit units are rampant.
Also, PCM relearning like you say might be an issue. But just throwing that out there.
Also, PCM relearning like you say might be an issue. But just throwing that out there.
