cobraboy

Okay, got the injector prob figured out, and now my 84 GSL-SE starts and runs like a top at 850 rpm..........for about 5 minutes. After that time, I smell something like burning grass and then the car abruptly dies. Starts right back up again, and runs for 5 minutes and then dies again.
Has anyone come across this before? or heard of anything similar?
Thanx in advance.

cobraboy

Forgot to mention in first post....84 gsl-se with new fuel pump, filters, strainer. All fuel lines and tank have been cleaned out...thoroughly.
Ran the engine last night, died exactly five minutes. Got up this morning and ran it again with pressure gauges attached. Steady 37-40 psi on supply line, 1psi on the return. It died again after about 8 minutes of running. Just before it died, the engine began to sputter a little and the fuel pressure began to fluctuate and then drop down til there was none. It sounds a lot like a plugged fuel filter to me, but I was wondering if there was something electrical that could be regulating voltage to the fuel pump. Does the computer control the pump? And does it change the voltage at the pump?

RotaryEvolution

iTrader: (30)

the smell sounds similar to electrical components overheating. try feeling around various things like relays and the ECU to see if anything feels abnormally hot.

be sure your battery connections at both ends(battery and engine) are clean and tight.

also check voltage to the pump, see if it is turning off the voltage before the fuel pressure dies off. if it is losing voltage your AFM may be the culprit since it has a fuel pump circuit that only turns the pump on when the AFM vane is beyond a certain position. FCs have a big problem with the fuel pump circuit in the AFM, it is caused by the AFM itself or vacuum leaks allowing the vane to close just enough to turn the pump off.

cobraboy

okay. voltage to the pump varies as it runs....anywhere from 12.61 to 11.46 with blower motor running (voltage at the battery remains stable at 14.3v). When the car dies, the voltage quickly diminishes.....it doesn't just drop from 12v to 0. I put in another fuel filter just to be sure, but no change. If the AFM is at fault here, how can I test it? Is it possible to use the fuel pump jumper connector, wire in a switch and bypass that function of the AFM?
Thanx in advance

RotaryEvolution

iTrader: (30)

jumper the test connector and see if it runs through the usual window. also check for vacuum leaks with a can of carb cleaner.

cobraboy

Saga continues... jumpered the fuel pump short connector. Started and ran for 15 minutes. After that time, the fuel pressure dropped to ten psi, but voltage went from 12.5v to 13.3v at the pump. Prior to all of this, I installed a new fuel filter and omitted the in-line cone filter. Still don't understand where the problem stems from unless the new strainer is plugging up (though the strainer is huge and the tank is clean). How much pressure should be in the return line?
Thanx Rotary Evolution for your help thus far

cobraboy

Got it figured out. Has something to do with the signal from the AFM or ECU, or could be a weak fuel pump relay, but after installing a new relay and rewiring the pump through that relay, the pump is running at full capacity and the car does not die. Now to fix the lag when first punching the gas, and she'll be on the road.