Walbro pump out, but other issues maybe

[JNR]

I have had some recent issues with my Sy dying while driving down the road. Typically it runs fine until I switch on the AC. After running the AC, the truck has run erratically and actually died on me three different times. The first two times the truck would not start immediately, and then after switching off the AC it would start and run again. Yesterday evening I thought I would test the AC theory again on the way home from work. Sure enough, about 5 miles after I switched the AC on, the truck cut-out, restarted, then suddenly died. I coasted to the side of the interstate, but this time no go on the re-start. Its good to have triple AAA when you are a SY owner..thats for sure.

So here is what I found after troubleshooting up to this point.

0) No codes present other than the standard 12 code flashed three times at the start.

1) Truck has plenty of battery power and starter spins the engine with no problem.

2) Pulled the power lead connecting the AC unit to make sure the unit wasn't shorting out for some reason. No change

3) Pulled a plug wire and inserted a fresh plug I had in the parts bin, and had good strong spark. Truck has newer wires, cap and rotor.

4) When switching the ignition on I could hear the Walbro hi-flow FP chatter-up like normal so I assumed the FP was good. Truck also has a new billet FP regulator with new hoses.

5) Even with all of the attempts to start no gas smell like it was flooded indicating gas is not getting past the injectors.

6) Just to be on the safe side I double checked the ECMB fuse. Not blown. Pulling the fuse resulted in no noise from the FP. Re-inserted a new fuse just to make sure and the FP was spinning-up as before.

7) Knowing that the ignition module provides reference pulse for the injectors and having an extra one available I changed the ignition module out. No change

8) I dropped the ECU to make sure the prom was seated well and that the wire connectors were all seated firmly with no crimping. Even replace the stock prom-pack with an ATR I have sitting in my bin. No changes.

9) Even though the FP is making noise like its working, I slapped my FP gauge on the rail and turned the ignition on. No FP noise. Turn the engine over. No pressure indicated on the gauage. Hitting the purge button, no pressure on the gauge hose. Hmmm... shoulda checked that first eh???

10) Removed the FP gauge and sat there for a minute then turned the ignition back on and could hear the pump again. Double checked the tank to bed ground and then reconnected the FP gauge again with the exact same results as the first time.

Now based on the results of my tests ....I assume the the Walbro pump is dead, or dying (which really pi$$e$ me off considering its just been in the truck for about 15-20k miles probably). I am also wondering why the problems seem to pop-up only when I was running the AC though? Maybe the added load on the power was aggravating an already bad pump? My main concern is that the AC is not causing some other kind of electrical problem which is the true root of my problems. The last thing I want is to put in another FP and then have the AC system kill it. Any thoughts on this would be appreciated.

Well I for one am not looking forward to pulling my bed again to replace the FP again. If anyone knows of any other decent fuel pump options for the Sy let me know, otherwise I guess I will try and buy another walbro and try my luck again.

Thanks

Jeff

 

[Raist103]

Re: Walbro pump out, but other issues maybe

is your pump hot wired if so is the fuse good? is your filter clogged?

 

[JNR]

Re: Walbro pump out, but other issues maybe

The pump is not hotwired and is fused though the ecmb fuse which is good. The fuel filter was changed when I installed the Walbro pump. Both pump and filter have about 15-20k miles on them. I havent checked or replaced the filter yet; but will do so just to be on the safe side before replacing my fuel pump.

Is there a fuel pump relay as well? I seem to remember that there might be a fuel pump relay on the firewall. Can anyone confirm that?

Thanks for the ideas guys!

JR

 

[JNR]

Re: Walbro pump out, but other issues maybe

Raiste103, I should probably run a seperate circuit for the fp to make sure its on its own fuse with adequate gauge wiring. Looks like I may get the chance to make that change in the near future.

Thanks again

JR

 

[V]

Re: Walbro pump out, but other issues maybe

This thread might help you a bit: http://www.syty.net/forums/showthread.php?p=406193

No in-cab FP gauge? Get one.

Instead of removing the bed, try raising it. Raising the bed is a one-man job...less chance of bed scratches or broken cladding. Remove all bolts, then just lift the left-rear corner of the bed (behind rear tire) off the frame to get enough headroom at the tank. I start at 6 inches of lift and support the bed with blocking or stands. I removed my bed once and swore never to do it again. :tdown: I've changed out pumps on 4 trucks with the easier "raise" method.

 

[JNR]

Re: Walbro pump out, but other issues maybe

Hmmm... I need to do something different with the bed situation. If I had a nice engine hoist I could use it to raise the bed and then block it somehow. Last time I swear I thought I herniated myself, and I am not keen on doing that again. Thanks for the tips guys.

Jeff

 

[JNR]

Re: Walbro pump out, but other issues maybe

V that link is excellent ...thanks again!

JR

 

[SY2932]

Re: Walbro pump out, but other issues maybe

.Instead of removing the bed, try raising it. Raising the bed is a one-man job...less chance of bed scratches or broken cladding. Remove all bolts, then just lift the left-rear corner of the bed (behind rear tire) off the frame to get enough headroom at the tank. I start at 6 inches of lift and support the bed with blocking or stands. I removed my bed once and swore never to do it again. :tdown: I've changed out pumps on 4 trucks with the easier "raise" method.

Yup you got that right . Here's a write up that I did to help out the all the syclone owners out there. Me and my bud did a fuel pump swap in my S10 a few years ago in about 35 minutes start to finish without taking the bed off. LOTS easier to do.

 

[Flyin Ryan]

Re: Walbro pump out, but other issues maybe

Did you try switching the fuel pump relay with the ac relay? there the two above the brake booster on the driver side.

 

[V]

Re: Walbro pump out, but other issues maybe

Yup you got that right . Here's a write up that I did to help out the all the syclone owners out there. Me and my bud did a fuel pump swap in my S10 a few years ago in about 35 minutes start to finish without taking the bed off. LOTS easier to do.

Been away from the forum, so I missed that thread. Nice write up Mike. :tup:

 

[JNR]

Re: Walbro pump out, but other issues maybe

ok...switched out the relays but no go. I am thinking the new pump and wiring harness from Racetronix may be the deal this time around.

 

[Gmoney]

Re: Walbro pump out, but other issues maybe

Ya Racetronix harness is the s#$t...

 

[JNR]

Update ......Re: Walbro pump out, but other issues maybe

Update ......Re: Walbro pump out, but other issues maybe

Well I am sitting waiting for AAA again with similar sypmtoms again . This truck is killing me.... . Since my last post, I bought and installed a new Walbro and Racetronix Harness . After the install the truck started right up and seemed to run fine for about five days. As I was making an early run to meet some guys for a business trip, I got on it a bit at the stoplight. Not WOT, but close. Suddenly the truck went into a hard stall and then I am coasting a dead truck into the parking lot.

Fuel is nearly full the fuses on the racetronix harness and ECMB are both good with 12 volts at the fuse point. I can hear the pump sound-off when the key is turned. FP tester says no pressure at the rail though. The truck also has a brand new ignition module in it. Well I am getting to apoint where I am running out of ideas. Any thoughts guys?

 

[skipztt]

Re: Walbro pump out, but other issues maybe

are u saying when you turn your key to "on", you can hear the pump go "out" or "off"? maybe i read it wrong. check the afpr, maybe the vaccum to the afpr. maybe a vaccum leak somewhere.

 

[JNR]

Re: Walbro pump out, but other issues maybe

Thanks for the feedback..

Sorry for not being clear on my comments. When I have someone turn the key to the on position, I can hear the new pump whine/spin-up as though its being energized. Even so, the fuel rail is not pressurized as my pressure tester does not budge. Typically my other walbro would make a whine accompanied with a stutter sound as it pressurized the rails/system. The old pump was making zero noise with no pressure when I replaced it with the new Walbro and the Racetrononix harness.

After replacing the Walbro and installing the Racetronix harness the new pump had a bit louder whine than the old Walbro, and also had the stutter sound. I knew it would start once I heard that stutter sound, and it did. As is after the stall-out I am back to a whine/spin-up sound coming from the FP, but it is not pressurizing the fuel rails. I have checked all the grounds, fuses, etc, and I did give my billet AFPR a cursory look and all vacuum lines are in place and not kinked or anything. I will do some additional checks on the AFPR, as logically it would be a possible culprit for sure and it does seem like fuel is not getting past that point.

I know the ignition module provides a reference for fueling the injectors and that can also cause problems. I have a new module in there, and removed and checked all of my connections again and re-installed. I have cleaned and re-set my grounds including the ECU grounds on the intake. I have also removed the ecu again this afternoon and removed and inspected all of the wiring connectors and checked for loose or shiner wires. Also checked and re-seated the ECU.

Other thoughts have been that the alternator is bad and when it gets spun-up has a winding that is going to short and causing problems. Checking the voltage on the back side of the alternator though, I have 12 volts being fed out to the Racetronix harness/fuse. Another thought or concern is that the coil ties into the ignition module, and that it might be causing problems of some sort? I have checked all the wiring connectors on the coil and the wires/caps/plugs are all pretty new and look excellent. If I pull a plug wire and insert another plug to check fire, I do have fire, but nothing to write home about...kinda weak looking to be honest and a little concerning. Again the truck was running great with the new pump, and then under heavy throttle just stalled hard.

Btw- I have had this happen numerous times over the years, and have never been able to track it down, but now it seems like it is manifesting itself in a way that is more of a hard failure this time around.


Thanks
Jeff

 

[SY2932]

Re: Walbro pump out, but other issues maybe

Apply 12 volts to the fuel pump test connector and see if you get pressure or not:

"Applying 12 volts to fuel pump test connector to troubleshoot fuel pump or set fuel pressure with vacuum line still connected and motor off (note fuse for safety)."

A member on here has an issue with the rubber line that connected in place of the pulsator blowing out. Never got to the root cause of that. Seems some line may have been included with fuel pumps that wasn't meant to be submerged in gas...

 

[JNR]

Re: Walbro pump out, but other issues maybe

Problem resolved today. After checking my vacuum lines and tweeking my AFPR I still had no results. So I picked up a new coil today and, after cussing those tiny hard to reach bolts, I finally got it installed. Not really expecting any results, I was almost surprised when the truck immediately started up! So I decide to re-set my fuel pressure and hook up my fuel pressure tester.

Now here is where the story gets interesting. I turn on the key to energize the Fp to check the pressure and to my surprise ...... no pressure reading! I turned the truck over and it fired right up, but still no pressure reading. Hmmm...??? I disconnect the fp tester connector and look into the end of it, and it is missing the little rubber seal and more importantly it is missing the litte valve stem.

I cannot F@$#ing believe it. The tester is only about a year old and has hardly been used, and I am thining that time I may have used it with its little adapter which does have the seal and valve stem. Man all those tests that were absolutely worthless but headed me down the wrong troubleshooting path.

Well the good news is I have a fresh walbro and a nicely made Racetronix FP wiring harness in my truck. The bad news is that I could have saved a couple of hundred dollars and fixed the truck with a lowly $20.00 coil. Moral of the story is always double check your tools, and even though you have spark be concerned if it is erratic or weak looking. Just to reiterate, the symptoms were cutting out,, stalling then re-firing, and then stalling under load and not re-starting. Problems became worse during the heatwave which fits the bad coil situation to a "T".

Thanks for everyones feedback..

Jeff

 

[SY2932]

Re: Walbro pump out, but other issues maybe

Good to hear that you got it figured out

! I did a write up how to check a coil a few years ago here.

 

[JNR]

Re: Walbro pump out, but other issues maybe

Thanks for the link to the coil testing info. That coil has been causing intermittent problems fo quite a while. I have been working out of state for the past several years and the truck just hasn't been driven much. I am just torqued that I didn't do a closer inspection of my FP tester and instead assumed it was giving an accurate reading. I must be getting senile in my old age. One item I am definitely going to get is FP gauge. Had my truck been equipped, I would have known the fuel pressure was not an issue.

Thanks again

JR