Hello all,
I have been reading the posts for awhile and now have a question. I am helping a friend work on a 89 XLT with the 5.8L and E40D transmission. Anyway it seemed to have a bad in-line fuel pump, fuel gauge showed only the low flow working. I replaced the in-line pump, and it started right up and then proceeded to stumble and stall, once it warmed up. Now it will start rev up to 2000 RPM for 3-5 seconds and stop, and it won't turn over for a few more minutes. Following some of the other posts I replaced the filter, ICM, and ignition switch. The pressure gauge shows the in-line working and then it just drops off when the engine dies. I pulled the codes and all I got was the EVP circuit was out of limits. Any idea of where to proceed would be greatly appreciated.

 

what is the fuel pressure? that bronco will also have 2 pumps. the frame mounted one and the intake pump. sounds to me like the intake pump is bad. but you need to check your fuel pressure at the rail first.

 

I would also check and clean the I A C valve.

 

I checked the pressure at the fuel rail and it passes the pressure test for the in-tank pump, and it also rises up with the frame rail pump. It starts nicely and idles and then dies out after 3-5 seconds or if you give it gas. Is there a switch from one circuit to another after the engine starts? I will also clean out the IAC this afternoon.

Thanks,

 

Another update the pressure at the rail is 30p.s.i. while idiling, and it stays within the boundaries when the throttle is opened. But then the pressure just drops off randomly. Could that be the fuel pressure regulator? I also cleaned out the mass airflow sensor and it seems to be working all right.

 

89 bronco wont have mass air. 30 psi is to low of pressure. 39-45psi is proper fuel pressure. its possible the regulator is bad, if you pull the vacum line from the top of the FPR and gas comes out of it then its bad. have you replace the fuel filter as well?

 

I would swap the fuel pump relay with the head light relay and see if the pump still dies.
It sounds like the relay may be faulting open.

 

Did you resolve the issue my bronco is having the same issue on a 5.0