KimoYogi Posted November 12, 2002 Report Share Posted November 12, 2002 I need some help, running a 500 hp bosch fuel pump, TEP four injector MPI, 294 hydraulic lifter cam, MSD ignition, haltech F9A computer, haltech A/F indicator, adjustable boost control set at 11 psi as indicated on a HKS boost indicator and 2 valve head. My problem is when reaching 4,000 rpm in the first three gears my engine starts to die. The engine is even now starting to act ugly as well in fourth gear. The A/F indicator being monitored at this time of frustration was running full rich up to 4 grand is now starting to oscillate between full rich and stoich with the engine sputtering at the same time. It appears that it is starving for fuel. This weekend I replaced the engine fuel filter for the second time and checked both filters in the tank not finding any contamination or clogged elements. I have not checked pump output pressure or the fuel regulator yet. These two items are on my list of things to be checked as well. Has anyone experienced a problem such as this with their Quest and if so what was the corrective action? The engine runs fine until it is nailed and then the problems start as previously addressed. Needless to say I am very fustrated at this point in time. Oh yeah, the tach is working whenever it decides to, very intermittent in operation...... most of the time it is just hanging in at 0 rpm. Anyones thoughts would certainly be appreciated. Link to comment Share on other sites More sharing options...
KimoYogi Posted November 13, 2002 Author Report Share Posted November 13, 2002 I forgot to add in the original post, whenever I let up after the engine stumbles and and sputters, it recovers and is ok until again reaching approximately 4 grand and the problem is again there.... KimoYogi Link to comment Share on other sites More sharing options...
cudabnu Posted November 13, 2002 Report Share Posted November 13, 2002 What size fuel line are you using? If you are using the stock line, it is not big enough to carry the amount of fuel you need. I'd put a fuel pressure guage on so you can monitor the fuel pressure while you are nailing it! Link to comment Share on other sites More sharing options...
heefner Posted November 14, 2002 Report Share Posted November 14, 2002 its not alway pressure but some times volume. You should be running an EGT to see what temp your at when it starts to fall. Also check the exhaust. Are you running a cat? it might be clogged espicially if it was running rich. Link to comment Share on other sites More sharing options...
ESIrType? Posted November 14, 2002 Report Share Posted November 14, 2002 Change your cap and rotor lately? My brother had the same problem on his 86. I tried pulling the coil wire out of the cap. It came out, without the end on it. I believe the cap/rotor was old and was out of clearence. It burnt the coil wire were the brass insert is, on the cap side. It did the samething also, 4000 and stumbling. He replaced the cap/rotor & coil wire, now it's fine. Link to comment Share on other sites More sharing options...
KimoYogi Posted November 14, 2002 Author Report Share Posted November 14, 2002 I am not running a cat at all, TEP down pipe and straight 21/2 inch pipe to muffler. Don't think muffler is clogged. Have a EGT in car but not connected and have a bung to install the sensor, but without sensor at this time. Old sensor is bad. You know where a good place might purchase a sensor that will work? Link to comment Share on other sites More sharing options...
heefner Posted November 14, 2002 Report Share Posted November 14, 2002 Jim summitt or jegs sells the probe if thays what you mean by sensor. Its a K or J type, can't remmeber which, (red and yellow) thermal couple that they use. Link to comment Share on other sites More sharing options...
KimoYogi Posted November 14, 2002 Author Report Share Posted November 14, 2002 Appreciate the info regarding where to find a "probe" ordering one tonight... Link to comment Share on other sites More sharing options...
Quest4Power Posted November 14, 2002 Report Share Posted November 14, 2002 most EGT gauges use the K type thermocouple... Link to comment Share on other sites More sharing options...
Shelby Posted November 16, 2002 Report Share Posted November 16, 2002 its not alway pressure but some times volume. Â You should be running an EGT to see what temp your at when it starts to fall. Â Also check the exhaust. Â Are you running a cat? Â it might be clogged espicially if it was running rich. boy you got that right Heefner , you have to concider the smallest fitting or restriction in the entire fuel delivery line , cause that will be the limeting part for the entire fuel supply, simply due to the control'd fuel pressure , atention has to be paid to the fittings use to connect the lines to the fuel filter and all even if going to a 3/8 steel fuel line a simple brase fitting with too small a pass thru hole will screw up the whole thing , and our fuel line and the banjo fitting weren't design'd to pass 2 or 3 times the stock flow of fuel monitoring the fuel system pressure at all times when setting up a MPI or any hi performance system is a must , Link to comment Share on other sites More sharing options...
Frank Posted November 21, 2002 Report Share Posted November 21, 2002 I have a question for you. If you ease it up to 4k or so without building a bunch of boost, does it run fine? It sounds to me like it is ignition related and not fuel. How much boost are you running? it might be time for some #8 plugs. What is you total timing? timing @ 4k? What engine management are you running? Frank Link to comment Share on other sites More sharing options...
fastquest Posted December 1, 2002 Report Share Posted December 1, 2002 Everyone forgot one thing! Whenever you run higher than stock boost, you need toadd a fuel cut defencer,it's made by jet @ around 159.00. You can add this to an 86. If you have a 87+ you must send in your computer to TEP for reprogramming. I am having the same probrem you described but I have the defencer on order. Link to comment Share on other sites More sharing options...
Joel Posted December 3, 2002 Report Share Posted December 3, 2002 There is no fuel cut on an 88+, the "fuel cut" is similar to a 1g DSM (non-existant)... the car will run at whatever boost you want as long as you dont overrun the MAF. Overrun the MAF and the car acts like s*** and wont drive right if you keep your foot in it (similar feeling as fuel cut). Joel Link to comment Share on other sites More sharing options...
Tim_C. Posted December 3, 2002 Report Share Posted December 3, 2002 We are talking MSD & Haltech here. Read the first post again. Did you cut the right wires for the MSD? It may not be configured right. Does it somehow have the wrong RPM limiter in it? Your tach is freaking, so maybe the RPM signal to the MSD is freaked, so even if you have a 7K RPM rev limiter in it, it thinks it is at 7K when really it's at 4K? You have NO OTHER WIRES HOOKED TO THE COIL, OTHER THAN MSD, correct? If you do have your other wires hooked to the coil, then that's the problem for sure. That's why the tach is screwed, and the reason for the IGNITION CUT. Man, don't even think of firing it up without knowing what the FP is at all times, especially at 4K RPM under Boost. Like Frank is saying, check your full timing advance, & when it comes in at? Do you have the Boost Timing Master MSD? Is the blow-off valve holding? They can release if they aren't stiff enough, but then it would want to go rich moreso than lean/stoich from rich. Can that Haltech print out a sequence of events, so you can see what's happening when? Check that. Tim C. Link to comment Share on other sites More sharing options...
Joel Posted December 4, 2002 Report Share Posted December 4, 2002 Your haltech does datalogging, I know myself (and I'm sure Tim_C) would look over the logs and give you advice. Datalog and email or pm me. Joel Link to comment Share on other sites More sharing options...
autotr8er Posted December 26, 2002 Report Share Posted December 26, 2002 There is no fuel cut on an 88+, the "fuel cut" is similar to a 1g DSM (non-existant)... the car will run at whatever boost you want as long as you dont overrun the MAF. Overrun the MAF and the car acts like s*** and wont drive right if you keep your foot in it (similar feeling as fuel cut). Joel So how do you modify the MAF so you car run higher boost? Link to comment Share on other sites More sharing options...
columbusquest Posted September 20, 2006 Report Share Posted September 20, 2006 I have a haltech E11V2 and had the exact same issue. To test it, give her hell till about 3500 rpm then change your ignition trigger angle about 10 degrees and see if you can get her reving past 4000rpm. If so, then you know for sure that it's an ignition issue. Then you can play with the igition map to fully correct the issue. Link to comment Share on other sites More sharing options...
Truth Posted September 20, 2006 Report Share Posted September 20, 2006 good lord this thread was four years ago :shock: Link to comment Share on other sites More sharing options...
madmitch Posted September 20, 2006 Report Share Posted September 20, 2006 wideband is your friend. Link to comment Share on other sites More sharing options...
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