Problems with my V-8 conversion!

OneBad91 · 10-14-2003, 07:16 PM

Well lets start from the top. I wrecked my 91 lx 5.0. Then i got a 90 LX 2.3. I had both the cars so i deiceded to do the coversion. I got my 5.0 and super fords mag. out that did an article on the conversion. I did everything by the book without really running into any problems at all until now. I go to start it and nothing it just turns over. I cracked open the thing on the fuel lines where you put a guage on and the little sprit of air comes out and no fuel. I know the fuel lines were full of air becuase i had to switch fuel lines, but what i think the problem is is that the fuel pump is turning on, and i have no idea why because i didn't mess with any of that. So if anyone has any ideas of has been through it please help me.
Brian

OneBad91 · 10-14-2003, 07:46 PM

I just talked to a guy not to long ago and he said my problem was that the cars were different years and that the wiring harness that is under the dash isn't lining up with the wiring under the hood. Not sure what to think now.

mustangII460 · 10-14-2003, 08:10 PM

Try reseting the inertia switch in the trunk. If that don't work it may be your wiring.

QuantumMotorsports · 10-14-2003, 10:44 PM

I have heard that the wiring did change, but i'm not sure. See if you can find out what pin on the computer is supposed to kick the fuel pump relay for each car (Chiltons manual) Also, this guy, PKRWUD, knows a lot about wiring harnesses. Give him a hollar.

QuantumMotorsports · 10-14-2003, 10:51 PM

Hey man, I just realized, if the entire lines are full of air, you're going to have to either crank the hell out of the motor to clear the air, or turn the key to on, like you're about to start it, and either hook up a pressure gauge with a bleed hose like you're going to check the pressure on your fuel rail, or just push the little pin in the middle of the valve (looks like a tire valvestem) and let the air come out until fuel come out. the pump might cycle on while you do this. When you turn the key to on, does the fuel pump come on for just a second? It's supposed to do that until the fuel pressure gets up to like 40 PSI. it's got a switch that turns it off when the pressure is up. So it basically pressurizes the air and stops, so you have to open it up and let the pressure drop so the pump will kick on to push the fuel through and push the air out. Does that make sense? But if the pump is not coming on at all, ask PKRWUD.

OneBad91 · 10-15-2003, 08:12 PM

Its not coming on at all when i turn the switch on.

OneBad91 · 10-16-2003, 07:29 PM

Ok i hot wired the fuel pump to see if it works and it did. So then I tried to start the car and it start right up but when i left the key go back into the run position it shut off. So i think i have the fuel pump problem figured out but now the car just shuts off when the key is in the position.

Coolbreeze · 10-16-2003, 08:27 PM

When you did the swap, did you swap the dash harness also?? If you look behind the driver side strut tower where the engine harness and dash harness connect, how many plugs are there?? The 91 engine harness, should have one(redish) & the 90 haness ahould have 2(blk & gry).. If all this was changed then you have another prob...

Check the ground for the engine harness over by the starter relay. It should have a round plug on it and then a ring to ground it to the body....Also make sure the ground is on by the EEC...

tmoss · 10-17-2003, 07:22 AM

Wiring diagrams and EEC pinout for your car are at:

www.veryuseful.com/mustang/tech/engine

OneBad91 · 10-19-2003, 07:15 PM

Well all most all my problems are solved, I changed the underdash portion of the wiring harness and that took care of everything, the car runs and drives now. THe only thing I can't understand is my turning signals. They do not work, but the 4 way flashers work. I checked all the flashers and i changed the stwich. Anyone got any ideas?

10-14-2003, 07:16 PM	#1
OneBad91 Registered Member Join Date: Apr 2002 Location: York, PA Posts: 58	Problems with my V-8 conversion! Well lets start from the top. I wrecked my 91 lx 5.0. Then i got a 90 LX 2.3. I had both the cars so i deiceded to do the coversion. I got my 5.0 and super fords mag. out that did an article on the conversion. I did everything by the book without really running into any problems at all until now. I go to start it and nothing it just turns over. I cracked open the thing on the fuel lines where you put a guage on and the little sprit of air comes out and no fuel. I know the fuel lines were full of air becuase i had to switch fuel lines, but what i think the problem is is that the fuel pump is turning on, and i have no idea why because i didn't mess with any of that. So if anyone has any ideas of has been through it please help me. Brian __________________ 90 lx notchback:4cyl to 5.0 conversion, Mac 1 3/4 long tube headers, 3 inch pro chamber, al. radiatior, 3:73 gears, underdrive pulleys, GT-40 intake with 1" spacer, cold air intake, electric fan, pro 5.0 shifter, smog pump delete, a/c delete, windage tray, flowmasters, turn downs, subframe connectors, 5-lug conversion. Pro Tru forged pistions, Roush 200 heads, z303 cam, 30# injectors, 70 mm t-body, 255 lph fuel pump, 1.6 roller rockers, 7 qt. pan, high volume oil pump, fuel pressure regulator, MSD 6AL, MSD blaster coil, MSD pro billet distributer, 75mm mass air, and a hell of alot of money.

10-14-2003, 07:46 PM	#2
OneBad91 Registered Member Join Date: Apr 2002 Location: York, PA Posts: 58	I just talked to a guy not to long ago and he said my problem was that the cars were different years and that the wiring harness that is under the dash isn't lining up with the wiring under the hood. Not sure what to think now. __________________ 90 lx notchback:4cyl to 5.0 conversion, Mac 1 3/4 long tube headers, 3 inch pro chamber, al. radiatior, 3:73 gears, underdrive pulleys, GT-40 intake with 1" spacer, cold air intake, electric fan, pro 5.0 shifter, smog pump delete, a/c delete, windage tray, flowmasters, turn downs, subframe connectors, 5-lug conversion. Pro Tru forged pistions, Roush 200 heads, z303 cam, 30# injectors, 70 mm t-body, 255 lph fuel pump, 1.6 roller rockers, 7 qt. pan, high volume oil pump, fuel pressure regulator, MSD 6AL, MSD blaster coil, MSD pro billet distributer, 75mm mass air, and a hell of alot of money.

10-14-2003, 10:44 PM	#4
QuantumMotorsports Registered Member Join Date: Jul 2000 Location: Norman, Oklahoma, USA Posts: 597	I have heard that the wiring did change, but i'm not sure. See if you can find out what pin on the computer is supposed to kick the fuel pump relay for each car (Chiltons manual) Also, this guy, PKRWUD, knows a lot about wiring harnesses. Give him a hollar. __________________ Michael Black QuantumMotorsports Norman, OK 1984 LX Hatch 306 w/ TRW forged flat toppers, Comp Cams Magnum 292H, GT40P heads w/ 3 angle valve job, .550 lift springs, Angus Racing Roller Rockers, Weiand Stealth Intake, Holley 4150 650cfm carb, MAC 1 5/8 Long Tubes, Single Chamber Flowmasters, 91' T5 w/ Pro 5.0 shifter, Turbo Coupe 8.8 Rear w/ 3.55 gears, QA1 Motorsports tubular K member, no interior except steering wheel and seat. Coming soon: 6 or 8 point cage, Fuel Cell, Weld Draglites

10-14-2003, 10:51 PM	#5
QuantumMotorsports Registered Member Join Date: Jul 2000 Location: Norman, Oklahoma, USA Posts: 597	Hey man, I just realized, if the entire lines are full of air, you're going to have to either crank the hell out of the motor to clear the air, or turn the key to on, like you're about to start it, and either hook up a pressure gauge with a bleed hose like you're going to check the pressure on your fuel rail, or just push the little pin in the middle of the valve (looks like a tire valvestem) and let the air come out until fuel come out. the pump might cycle on while you do this. When you turn the key to on, does the fuel pump come on for just a second? It's supposed to do that until the fuel pressure gets up to like 40 PSI. it's got a switch that turns it off when the pressure is up. So it basically pressurizes the air and stops, so you have to open it up and let the pressure drop so the pump will kick on to push the fuel through and push the air out. Does that make sense? But if the pump is not coming on at all, ask PKRWUD. __________________ Michael Black QuantumMotorsports Norman, OK 1984 LX Hatch 306 w/ TRW forged flat toppers, Comp Cams Magnum 292H, GT40P heads w/ 3 angle valve job, .550 lift springs, Angus Racing Roller Rockers, Weiand Stealth Intake, Holley 4150 650cfm carb, MAC 1 5/8 Long Tubes, Single Chamber Flowmasters, 91' T5 w/ Pro 5.0 shifter, Turbo Coupe 8.8 Rear w/ 3.55 gears, QA1 Motorsports tubular K member, no interior except steering wheel and seat. Coming soon: 6 or 8 point cage, Fuel Cell, Weld Draglites

10-15-2003, 08:12 PM	#6
OneBad91 Registered Member Join Date: Apr 2002 Location: York, PA Posts: 58	Its not coming on at all when i turn the switch on. __________________ 90 lx notchback:4cyl to 5.0 conversion, Mac 1 3/4 long tube headers, 3 inch pro chamber, al. radiatior, 3:73 gears, underdrive pulleys, GT-40 intake with 1" spacer, cold air intake, electric fan, pro 5.0 shifter, smog pump delete, a/c delete, windage tray, flowmasters, turn downs, subframe connectors, 5-lug conversion. Pro Tru forged pistions, Roush 200 heads, z303 cam, 30# injectors, 70 mm t-body, 255 lph fuel pump, 1.6 roller rockers, 7 qt. pan, high volume oil pump, fuel pressure regulator, MSD 6AL, MSD blaster coil, MSD pro billet distributer, 75mm mass air, and a hell of alot of money.

10-14-2003, 08:10 PM	#3
mustangII460 Factoy Five Roadster Join Date: May 2000 Location: Sevier Co,Tennessee Posts: 1,681	Try reseting the inertia switch in the trunk. If that don't work it may be your wiring.

10-16-2003, 07:29 PM	#7
OneBad91 Registered Member Join Date: Apr 2002 Location: York, PA Posts: 58	Ok i hot wired the fuel pump to see if it works and it did. So then I tried to start the car and it start right up but when i left the key go back into the run position it shut off. So i think i have the fuel pump problem figured out but now the car just shuts off when the key is in the position. __________________ 90 lx notchback:4cyl to 5.0 conversion, Mac 1 3/4 long tube headers, 3 inch pro chamber, al. radiatior, 3:73 gears, underdrive pulleys, GT-40 intake with 1" spacer, cold air intake, electric fan, pro 5.0 shifter, smog pump delete, a/c delete, windage tray, flowmasters, turn downs, subframe connectors, 5-lug conversion. Pro Tru forged pistions, Roush 200 heads, z303 cam, 30# injectors, 70 mm t-body, 255 lph fuel pump, 1.6 roller rockers, 7 qt. pan, high volume oil pump, fuel pressure regulator, MSD 6AL, MSD blaster coil, MSD pro billet distributer, 75mm mass air, and a hell of alot of money.

10-16-2003, 08:27 PM	#8
Coolbreeze Registered Member Join Date: Oct 2000 Location: ~Columbus~GA~31909~ Posts: 156	When you did the swap, did you swap the dash harness also?? If you look behind the driver side strut tower where the engine harness and dash harness connect, how many plugs are there?? The 91 engine harness, should have one(redish) & the 90 haness ahould have 2(blk & gry).. If all this was changed then you have another prob... Check the ground for the engine harness over by the starter relay. It should have a round plug on it and then a ring to ground it to the body....Also make sure the ground is on by the EEC... __________________ Mike Blown~AOD'ed~331~ T-top~ 86GT Check out car on my page here ------ > ~~My 86GT T-top ~~

10-17-2003, 07:22 AM	#9
tmoss Registered Member Join Date: Mar 2003 Location: Saint Louis, MO Posts: 634	Wiring diagrams and EEC pinout for your car are at: www.veryuseful.com/mustang/tech/engine __________________ Tom (Torque) Moss 88Gt 5spd Vert, FLowmaster Catbacks, stock cam advanced 4° @ 108.5° ICL, NMRA prepped GT40P heads 1.85/1.55 valves and 1.7 rockers, MAC P headers Jet-Hot coated, 97 Exlporer intake (ported lower), TB and injectors. 277RWHP/330RWTQ (SAE). http://www.fastlanecars.com/

10-19-2003, 07:15 PM	#10
OneBad91 Registered Member Join Date: Apr 2002 Location: York, PA Posts: 58	Well all most all my problems are solved, I changed the underdash portion of the wiring harness and that took care of everything, the car runs and drives now. THe only thing I can't understand is my turning signals. They do not work, but the 4 way flashers work. I checked all the flashers and i changed the stwich. Anyone got any ideas? __________________ 90 lx notchback:4cyl to 5.0 conversion, Mac 1 3/4 long tube headers, 3 inch pro chamber, al. radiatior, 3:73 gears, underdrive pulleys, GT-40 intake with 1" spacer, cold air intake, electric fan, pro 5.0 shifter, smog pump delete, a/c delete, windage tray, flowmasters, turn downs, subframe connectors, 5-lug conversion. Pro Tru forged pistions, Roush 200 heads, z303 cam, 30# injectors, 70 mm t-body, 255 lph fuel pump, 1.6 roller rockers, 7 qt. pan, high volume oil pump, fuel pressure regulator, MSD 6AL, MSD blaster coil, MSD pro billet distributer, 75mm mass air, and a hell of alot of money.

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