88 lx 5.0 needs help!

pearce9906 · 12-05-2007, 10:36 PM

I have an 88 lx 5.0 hatchback, 5 speed tranny. Stock except for bbk shortie headers, bbk cold air intake, accell ignition and wires.
Two days ago the stock fuel pressure regulator blew, started pumping gas through the vacuum port, straight into the plenum. Motor flooded out and died instantly, since then I replaced the bad reg with oem part, turns out it was a new BAD part, put another one on today, it works fine, but now I have a dead miss, sounds like at least two cylinders are dead, no knocking, no rattling. Doesn't sound like a bent pushrod, changed plugs before I put the first replacement reg on, haven't pulled the plugs back out after the second new reg was put on though. Any thoughts would be great.
If you need more info about the car just ask, I will tell all I can, only had it about a month, not sure about much history with it, but I will share all i can.

DaLe five OH! · 12-05-2007, 11:49 PM

change all the plugs out again

Dark_5.0 · 12-06-2007, 12:12 PM

Yeah change the plugs again. If that doesnt work check the temp of the header tubes to find a potentially dead cylinder.

pearce9906 · 12-06-2007, 12:28 PM

Thanks for the direction guys. I work tonight so I'll try swapping out the plugs first thing in the morning.
By the way, do you think it's possible fuel would have gotten into the sensors through the vacuum lines and ruined them? like the MAP sensor and the rest that have vacuum lines attached?

Thanks again, I'll let you know what I come up with.

Dark_5.0 · 12-06-2007, 04:56 PM

Quote:

Originally Posted by pearce9906

Thanks for the direction guys. I work tonight so I'll try swapping out the plugs first thing in the morning.
By the way, do you think it's possible fuel would have gotten into the sensors through the vacuum lines and ruined them? like the MAP sensor and the rest that have vacuum lines attached?

Thanks again, I'll let you know what I come up with.

I hydrolocked my 300zx last summer and it kept fouling the plugs cause water was pooled in the intake manifold. I removed all the spark plugs and jacked the car up on one side high as it would go to make all the pooled water run out of the intake and into the cylinders, then I turned it over in 20 second burst a few times and that seemed to work pretty well. All the water shotout the spark plug holes.

pearce9906 · 12-07-2007, 02:20 AM

This one was hydrolocked also, after the original regulator blew, before I changed plugs, when I took the old (original) plugs out, I turned it over in several short bursts and blew the fuel out of the cylinders, it was fuel. Yours was water?

Dark_5.0 · 12-07-2007, 07:19 PM

Quote:

Originally Posted by pearce9906

This one was hydrolocked also, after the original regulator blew, before I changed plugs, when I took the old (original) plugs out, I turned it over in several short bursts and blew the fuel out of the cylinders, it was fuel. Yours was water?

Yeah I drove through some deep water and well you know the rest.

pearce9906 · 12-14-2007, 12:48 AM

Well, I changed plugs out again, to no avail. EGR was bad, replaced it, as well as TPS, still not fixed. Noticed there were two vacuum solenoids on the right front inner fender on the the rear of the engine compartment that were damp with some gas, presumably from where the reg went bad and flooded the plenum and vacuum lines, I took them apart and cleaned them, that seemed to do the trick with getting the car running right and taking out the majority of the miss. But now I have severe idle surge, almost dropping to the point of killing itself, also running super rich. I've tried almost everything I can think of to narrow the problem down, but am having a heck of a time with it. Any ideas?
Keep in mind, I have just bought this car and don't have much idea about what mods previous owners have done to tune the car.

bailey_57 · 12-18-2007, 10:45 PM

did you replace the tps and set it? surging idle is a problem as old as the 5.0. if you go through a search for surging idle you probably will find quite a few threads. also before i had any mods, i had a surging idle and chased all the gremlins. i got rid of mine with a 1/8th in drill bit through the throttle blade. good luck.

pearce9906 · 12-19-2007, 01:56 AM

thanks for the reply baily_57, tomorrow is my day off so I plan to work on the car all day, hopefully I can chase my demon down, plan on setting the tps voltage, checking fuel pressure, checking compression, and possibly trying the codes, not throwing a check engine light tho, could mean the previous owner installed a chip or removed the bulb tho. Hopefully something will turn up tomorrow though, I am about at wit's end on this problem. Getting super frustrated. I'll post what I find. Thanks again.

USMC302 · 12-19-2007, 10:34 AM

Might be a good idea to throw in some new o2 sensors.

pearce9906 · 12-19-2007, 11:19 AM

Haven't checked the TPS voltage yet, but bought a code reader today, turns out I had a few codes, IAC valve, coolant sensor, which was my fault because I unplugged them whileengine was running, but also the fuel pump relay circuit was bad, pump is running all the time, which to my thinking would explain the rich condition and also the idle surge, if the motor is loading up with fuel at idle it would pretty much be flooding itself out. Correct? Also, the fuel pressure regulator is bad once again, I guess the pump running all the time is just building up too much pressure in the line and the diaphram in the reg is blowing out.

USMC302 · 12-19-2007, 11:45 AM

It's supposed to run all the time when the engine is running.. What makes you say the FPR is bad again? You need to set the TPS, before we try to point fingers at anything else....

pearce9906 · 12-19-2007, 06:33 PM

ECM says relay is bad. Trouble code 87. Also, even with the relay removed, fuel pump still runs when ignition is turned on, TPS voltage is now set at .96. Car runs, but still surging after about 3 minutes, also, fuel injecters are getting wet with fuel, on the outside. Not a leak on the fuel rail, it is a mist/smoke coming from around the injectors at about five minutes idle time, after the motor starts loading up with fuel.

Any idea why the fuel pump would run all the time (without the relay)?

USMC302 · 12-19-2007, 06:39 PM

two things......The pump should NOT run with the relay out. Your referring to the relay under the seat right? That is the fuel relay.

Second, if you see fuel mist from the injectors, something is def wrong. I would pull the injectors and get them tested or serviced, where on the injector is the fuel mist coming from, can you see it exactly?

pearce9906 · 12-19-2007, 06:46 PM

Yes, the fuel relay under the drivers' seat, the mist/vapor is coming from not from the injector, but from the intake around the injector seat, but only after the motor has started loading up with fuel, running rich.
If the fuel pump were running correctly, would it pulse on and off, or would it run all the time?
I know that GM fuel pumps pulse on and off based on back pressure in the line.

USMC302 · 12-20-2007, 10:30 AM

Your injectors control the pulse of fuel on the stangs, not the pumps. Swap the regulator out and check the injectors O-rings, make sure you don't have any dry rotting and need replacement...

pearce9906 · 12-20-2007, 01:57 PM

Ok, thanks. I will try that, I've gotta work the next coupla evenings. It will probably be saturday before I can do much more work to it. I'll post what I find. Thanks.

pearce9906 · 12-22-2007, 05:55 PM

Ok, more info. Took the Ignition module to be tested today, turns out it was bad, replaced it with a new one. No change to my current problem. (just a refresher, pump relay out and pump still runs, two hots, one constant, one switch one power) Turns out the switch on power is the supply to the fuel pump, pink and black, started checking the harness, past owner had byassed inertia switch, hacking into the pump harness with direct switch on power, also bypassing the relay. I fixed all the hacking, put new relay in, but now have no power to the pump.

Trying to track down problem, this is what I have so far:
1. at the relay, there are five wires, one is constant, two pink and black (one runs in harness towards front of car, unsure of where it goes, i would like to find out if anyone knows, the second pink and black goes to fuel pump), one wire comes into relay from the inertia switch, and one goes from relay to the ecm.
2. Constant power is constant, obiously. Switch on sends power through the inertia switch back to the relay, then this power goes to the ecm.
3. How does the ecm open the gate to the pump?
4. If I probe the wire going to the ecm with a test light, the relay clicks open and the pump runs, still doesn't prime and shut off like I think it should when the car isn't running though.

Anyone have a GOOD wiring diagram of the fuel relay circuit? Good being the operative word there.

By the way, code 87 is now the only code being pulled.

pearce9906 · 12-22-2007, 10:09 PM

Ok, I replaced the EEC relay, still nothing from the pump. I shorted the test terminal out on the test plug and the pump fired up and worked fine, this leads me to believe the EEC is either not grounding good, or is fried. Anyone have anyidea where the EEC grounds at, other than the little black wire behind the kickpanel on the passenger side? I still don't want to believe the EEC is bad because everything else works on the car except the fuel pump and the cruise control, it just seems the EEC is not sending the signal to open the gate in the relay and send power to the pump, I have to believe that it is a failty ground. Any suggestions?

12-05-2007, 10:36 PM	#1
pearce9906 Registered Member Join Date: Nov 2007 Location: OHIO Posts: 20	88 lx 5.0 needs help! I have an 88 lx 5.0 hatchback, 5 speed tranny. Stock except for bbk shortie headers, bbk cold air intake, accell ignition and wires. Two days ago the stock fuel pressure regulator blew, started pumping gas through the vacuum port, straight into the plenum. Motor flooded out and died instantly, since then I replaced the bad reg with oem part, turns out it was a new BAD part, put another one on today, it works fine, but now I have a dead miss, sounds like at least two cylinders are dead, no knocking, no rattling. Doesn't sound like a bent pushrod, changed plugs before I put the first replacement reg on, haven't pulled the plugs back out after the second new reg was put on though. Any thoughts would be great. If you need more info about the car just ask, I will tell all I can, only had it about a month, not sure about much history with it, but I will share all i can.

12-05-2007, 11:49 PM	#2
DaLe five OH! Registered Member Join Date: Nov 2006 Location: Naples FL Posts: 106	Re: 88 lx 5.0 needs help! change all the plugs out again __________________ ZEX

12-06-2007, 12:12 PM	#3
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	Re: 88 lx 5.0 needs help! Yeah change the plugs again. If that doesnt work check the temp of the header tubes to find a potentially dead cylinder. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

12-06-2007, 12:28 PM	#4
pearce9906 Registered Member Join Date: Nov 2007 Location: OHIO Posts: 20	Re: 88 lx 5.0 needs help! Thanks for the direction guys. I work tonight so I'll try swapping out the plugs first thing in the morning. By the way, do you think it's possible fuel would have gotten into the sensors through the vacuum lines and ruined them? like the MAP sensor and the rest that have vacuum lines attached? Thanks again, I'll let you know what I come up with.

12-07-2007, 02:20 AM	#6
pearce9906 Registered Member Join Date: Nov 2007 Location: OHIO Posts: 20	Re: 88 lx 5.0 needs help! This one was hydrolocked also, after the original regulator blew, before I changed plugs, when I took the old (original) plugs out, I turned it over in several short bursts and blew the fuel out of the cylinders, it was fuel. Yours was water?

12-14-2007, 12:48 AM	#8
pearce9906 Registered Member Join Date: Nov 2007 Location: OHIO Posts: 20	Re: 88 lx 5.0 needs help! Well, I changed plugs out again, to no avail. EGR was bad, replaced it, as well as TPS, still not fixed. Noticed there were two vacuum solenoids on the right front inner fender on the the rear of the engine compartment that were damp with some gas, presumably from where the reg went bad and flooded the plenum and vacuum lines, I took them apart and cleaned them, that seemed to do the trick with getting the car running right and taking out the majority of the miss. But now I have severe idle surge, almost dropping to the point of killing itself, also running super rich. I've tried almost everything I can think of to narrow the problem down, but am having a heck of a time with it. Any ideas? Keep in mind, I have just bought this car and don't have much idea about what mods previous owners have done to tune the car.

12-18-2007, 10:45 PM	#9
bailey_57 Registered Member Join Date: Mar 2000 Location: Berwick,Pa Posts: 127	Re: 88 lx 5.0 needs help! did you replace the tps and set it? surging idle is a problem as old as the 5.0. if you go through a search for surging idle you probably will find quite a few threads. also before i had any mods, i had a surging idle and chased all the gremlins. i got rid of mine with a 1/8th in drill bit through the throttle blade. good luck. __________________ '89 GT hatch back performer rpm intake, performer rpm cylinder heads, fms e-303 cam, kirban adj fp regulator, holley 65mm tb, harland sharp 1.6 roller rockers, alum driveshaft, 3.73 gears (283 rwhp, 303 rwtq new numbers with new heads)

12-19-2007, 01:56 AM	#10
pearce9906 Registered Member Join Date: Nov 2007 Location: OHIO Posts: 20	Re: 88 lx 5.0 needs help! thanks for the reply baily_57, tomorrow is my day off so I plan to work on the car all day, hopefully I can chase my demon down, plan on setting the tps voltage, checking fuel pressure, checking compression, and possibly trying the codes, not throwing a check engine light tho, could mean the previous owner installed a chip or removed the bulb tho. Hopefully something will turn up tomorrow though, I am about at wit's end on this problem. Getting super frustrated. I'll post what I find. Thanks again.

12-19-2007, 10:34 AM	#11
USMC302 Registered Member Join Date: Apr 2001 Location: Gallatin, Tn Posts: 1,326	Re: 88 lx 5.0 needs help! Might be a good idea to throw in some new o2 sensors. __________________

12-19-2007, 11:19 AM	#12
pearce9906 Registered Member Join Date: Nov 2007 Location: OHIO Posts: 20	Re: 88 lx 5.0 needs help! Haven't checked the TPS voltage yet, but bought a code reader today, turns out I had a few codes, IAC valve, coolant sensor, which was my fault because I unplugged them whileengine was running, but also the fuel pump relay circuit was bad, pump is running all the time, which to my thinking would explain the rich condition and also the idle surge, if the motor is loading up with fuel at idle it would pretty much be flooding itself out. Correct? Also, the fuel pressure regulator is bad once again, I guess the pump running all the time is just building up too much pressure in the line and the diaphram in the reg is blowing out.

12-19-2007, 11:45 AM	#13
USMC302 Registered Member Join Date: Apr 2001 Location: Gallatin, Tn Posts: 1,326	Re: 88 lx 5.0 needs help! It's supposed to run all the time when the engine is running.. What makes you say the FPR is bad again? You need to set the TPS, before we try to point fingers at anything else.... __________________

12-19-2007, 06:33 PM	#14
pearce9906 Registered Member Join Date: Nov 2007 Location: OHIO Posts: 20	Re: 88 lx 5.0 needs help! ECM says relay is bad. Trouble code 87. Also, even with the relay removed, fuel pump still runs when ignition is turned on, TPS voltage is now set at .96. Car runs, but still surging after about 3 minutes, also, fuel injecters are getting wet with fuel, on the outside. Not a leak on the fuel rail, it is a mist/smoke coming from around the injectors at about five minutes idle time, after the motor starts loading up with fuel. Any idea why the fuel pump would run all the time (without the relay)?

12-19-2007, 06:39 PM	#15
USMC302 Registered Member Join Date: Apr 2001 Location: Gallatin, Tn Posts: 1,326	Re: 88 lx 5.0 needs help! two things......The pump should NOT run with the relay out. Your referring to the relay under the seat right? That is the fuel relay. Second, if you see fuel mist from the injectors, something is def wrong. I would pull the injectors and get them tested or serviced, where on the injector is the fuel mist coming from, can you see it exactly? __________________

12-19-2007, 06:46 PM	#16
pearce9906 Registered Member Join Date: Nov 2007 Location: OHIO Posts: 20	Re: 88 lx 5.0 needs help! Yes, the fuel relay under the drivers' seat, the mist/vapor is coming from not from the injector, but from the intake around the injector seat, but only after the motor has started loading up with fuel, running rich. If the fuel pump were running correctly, would it pulse on and off, or would it run all the time? I know that GM fuel pumps pulse on and off based on back pressure in the line.

12-20-2007, 10:30 AM	#17
USMC302 Registered Member Join Date: Apr 2001 Location: Gallatin, Tn Posts: 1,326	Re: 88 lx 5.0 needs help! Your injectors control the pulse of fuel on the stangs, not the pumps. Swap the regulator out and check the injectors O-rings, make sure you don't have any dry rotting and need replacement... __________________

12-20-2007, 01:57 PM	#18
pearce9906 Registered Member Join Date: Nov 2007 Location: OHIO Posts: 20	Re: 88 lx 5.0 needs help! Ok, thanks. I will try that, I've gotta work the next coupla evenings. It will probably be saturday before I can do much more work to it. I'll post what I find. Thanks.

12-22-2007, 05:55 PM	#19
pearce9906 Registered Member Join Date: Nov 2007 Location: OHIO Posts: 20	Re: 88 lx 5.0 needs help! Ok, more info. Took the Ignition module to be tested today, turns out it was bad, replaced it with a new one. No change to my current problem. (just a refresher, pump relay out and pump still runs, two hots, one constant, one switch one power) Turns out the switch on power is the supply to the fuel pump, pink and black, started checking the harness, past owner had byassed inertia switch, hacking into the pump harness with direct switch on power, also bypassing the relay. I fixed all the hacking, put new relay in, but now have no power to the pump. Trying to track down problem, this is what I have so far: 1. at the relay, there are five wires, one is constant, two pink and black (one runs in harness towards front of car, unsure of where it goes, i would like to find out if anyone knows, the second pink and black goes to fuel pump), one wire comes into relay from the inertia switch, and one goes from relay to the ecm. 2. Constant power is constant, obiously. Switch on sends power through the inertia switch back to the relay, then this power goes to the ecm. 3. How does the ecm open the gate to the pump? 4. If I probe the wire going to the ecm with a test light, the relay clicks open and the pump runs, still doesn't prime and shut off like I think it should when the car isn't running though. Anyone have a GOOD wiring diagram of the fuel relay circuit? Good being the operative word there. By the way, code 87 is now the only code being pulled.

12-22-2007, 10:09 PM	#20
pearce9906 Registered Member Join Date: Nov 2007 Location: OHIO Posts: 20	Re: 88 lx 5.0 needs help! Ok, I replaced the EEC relay, still nothing from the pump. I shorted the test terminal out on the test plug and the pump fired up and worked fine, this leads me to believe the EEC is either not grounding good, or is fried. Anyone have anyidea where the EEC grounds at, other than the little black wire behind the kickpanel on the passenger side? I still don't want to believe the EEC is bad because everything else works on the car except the fuel pump and the cruise control, it just seems the EEC is not sending the signal to open the gate in the relay and send power to the pump, I have to believe that it is a failty ground. Any suggestions?