Help me diagnose fuel pump issue
Thread Starter
Pro
Joined: Jun 2010
Posts: 517
Likes: 27
Help me diagnose fuel pump issue
So my car died several times last week...but I was able to get it running several times...now it will not start at all...I am not seeing any fuel pressure at the rail (with engine off). I jumpered 30 and 87 at the fuse box and am reading 11.97 volts at terminal 86 with the key on. I tried swapping horn relay into the fuel pump spot...so far no luck...car will crank, but not start...feels like it will almost start. How do I check the pump itself..can it be jumpered to stay on?
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
Here is the schematic for the pump. I also looked in my 2001 FSM and the motor leads also show as Gray and Black. If you jumper them with 12 volts and the motor does not work you know what your problem is.
I know the right side senders are different starting in 1999. It would appear the left side pump and sender are the same (did not change) but make sure you get the correct one in case there is a difference in the sender resistance.
I know the right side senders are different starting in 1999. It would appear the left side pump and sender are the same (did not change) but make sure you get the correct one in case there is a difference in the sender resistance.
Instructor
Joined: Nov 2002
Posts: 244
Likes: 12
From: IL
My buddy's 98 recently had similar symptoms. We ended replacing the fuel pump. You should meter out the relay to check grounds G-105 and S Pack. You will also find a PCM and constant hot relay slot. If You jump the relay and it does not start (no fuel pressure) you will need to move back to the fuel pump. The ground for the pump is mounted to the frame behind the left rear tire. From memory (?) there are four leads, A B C D on the pump connector. One ground, one to fuel sender, one to PCM, one constant hot, meter out the leads. The sender should be approx 5 volts, The PCM side will only be hot for approx 2 to 3 sec. If the other 2 check out ok it is probably the pump. If it is the pump be careful buying online, 2 different parts outlets baited and switched me. Last time I was on Rock Auto they still had a limited supply of Bosch Pumps. Hope this helps.
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
You jumper at the pump/connector. This way you rule in/out power supply and/or ground if it runs or not. Need to make sure you have a good ground. If you have any questions feel free to PM me with your number and we can discuss.
