I had a short break-down today. Kind of interesting story.

General Fiero Maintenance including oil changes, air filters, suspension refreshes, restorations, painting, etc.

Moderators: The Dark Side of Will, Series8217

AkursedX
Turbo-boostin!
Posts: 1078
Joined: Wed Nov 17, 2004 2:14 pm
Location: Lackawanna, NY

I had a short break-down today. Kind of interesting story.

Post by AkursedX »

Well today I spent most of my day out at the Woodward Dream Cruise. After sitting around for awhile checking out cars, my dad and I hopped in the Fiero to do a loop on Woodward. Now to those who don't know, you are pretty much driving 10-15mph in traffic for a pretty long stretch. We drove from 12-mile all the way up to the Pontiac loop and back. This was probably about 1.5 hours in 85+-degree weather. So this is pretty severe driving conditions. That being said, my coolant never got above 90*C, and everything seemed like it was running just fine.

So all of a sudden, I notice that my wideband jumps to 16.00 and then it starts running a bit froggy. It starts surging and fortunately I was able to pull onto a side street. I kill it and I pop the decklid and do a full check-over. I try to pull codes off the scangauge and nothing was there. We let it sit and cool 15-minutes of so and fire it up again. At first it seems ok, then we drive a couple of blocks and the same thing happens. This time, I notice that the fuel pump is making all sorts of crazy noises. So once again I get out and check everything out and everything seemed ok. I'm thinking that there might be an issue with the fuel pump. I had 1/2 tank of gas in it. My father has been a mechanic for 33-years and came up with a reasonable deduction. He figured that because of all the slow driving and idling in the heat, letting all the hot gas return back to the tank that the fuel was actually becoming so hot that I was sucking vapor into the lines and killing my fuel pressure.

This time we let is sit for over an hour. I then fired it up and *viola*, she's running like a champ. I made it to a gas station and topped off with some fresh, cool gas and did not have an issue the rest of the day. Weird. I just thought I'd share that story in case anyone else might face a issue like that.
'88 Fiero GT- 3800 Turbo Best E.T. 11.36 Best MPH 121.50 (Sold and gone)
2021 Hyundai Veloster-N (SCCA Solo D-Street)
2004 Mazda RX-8 (SCCA Solo STX)
WNY SCCA-Region Auto-X Program Chair
Jinxmutt
Posts: 991
Joined: Sat Feb 12, 2005 9:30 pm

Re: I had a short break-down today. Kind of interesting story.

Post by Jinxmutt »

Are you using a walbro? This is almost exactly like the issue I used to complain about with mine. Around town and typical driving, I had zero issues whatsoever. When I drive to school, I would get 8hrs or so into the drive and the pump would get louder and the car would run like shit. I swapped the pump out just in case, but sure enough, the 2nd one did it as well. I'm now running a bosch pump and the car hasn't done it yet. I'm not saying its something with the walbro itself getting hot, but I think it has something to do with the pump moreso than the gas. Just my opinion.
AkursedX
Turbo-boostin!
Posts: 1078
Joined: Wed Nov 17, 2004 2:14 pm
Location: Lackawanna, NY

Re: I had a short break-down today. Kind of interesting story.

Post by AkursedX »

Jinxmutt wrote:Are you using a walbro? This is almost exactly like the issue I used to complain about with mine. Around town and typical driving, I had zero issues whatsoever. When I drive to school, I would get 8hrs or so into the drive and the pump would get louder and the car would run like shit. I swapped the pump out just in case, but sure enough, the 2nd one did it as well. I'm now running a bosch pump and the car hasn't done it yet. I'm not saying its something with the walbro itself getting hot, but I think it has something to do with the pump moreso than the gas. Just my opinion.
Interesting hypothesis. You very well could be correct. And I am running a walbro pump. I have taken the car as long as a 4-hour trip with no issues. I'm sure the hot gas and weather were large contributing factors. It very well could have overheated the pump. It's good to know that you have had some similar issues. I will definitely keep an eye out for more issues.

What model bosch pump are you running for information's sake?
'88 Fiero GT- 3800 Turbo Best E.T. 11.36 Best MPH 121.50 (Sold and gone)
2021 Hyundai Veloster-N (SCCA Solo D-Street)
2004 Mazda RX-8 (SCCA Solo STX)
WNY SCCA-Region Auto-X Program Chair
Jinxmutt
Posts: 991
Joined: Sat Feb 12, 2005 9:30 pm

Re: I had a short break-down today. Kind of interesting story.

Post by Jinxmutt »

4 hours wouldn't have been long enough to 'limp mode' my walbro. It would definitely take up around 8hrs. Now, I'm running a Bosch "044" pump. Its an inline pump. I have a 100 micron steel filter before the pump and a 10 micron paper filter after the pump. The very first drive out with the new pump, the car ran like complete crap. As soon as I would even start to give the car any bit of throttle the afr would go way rich. In boost, the car wouldn't go at all. It would just sputter and pop, pegged rich. I had to pull so much injector from my tune to get back to decent afr levels. The car runs a HELL of a lot better now with the new pump and new tune.

My mounting 'system'
Image

Image


It's not the prettiest car underneath.. :) I drove the car down to charlotte wednesday night along with my buddy who was driving a 26 ft box truck. The trip took about 15 hours since the truck would struggle with hills, etc. I'm typing this on my way back to CT and the car had not a single fuel issue.

On the other hand, the bosch pump makes a buzzing noise. It's not an issue for me, but other people may complain because the pump can certainly be heard in the car.
User avatar
Aaron
I just wanna ride my motorcycle
Posts: 5957
Joined: Sun May 29, 2005 5:15 am
Contact:

Re: I had a short break-down today. Kind of interesting story.

Post by Aaron »

Very interesting. I too had a break down (My first) the other day. It was about 95* out, and I took the Fiero back to the Springs, which is about an hour drive. I'm doing a constant 85mph no problems, but I notice the engine is running warm, a lot warmer than usual. I couldn't really find a reason either, I hadn't been on boost since getting on the highway, had the intercooler going since I started the motor, very low loads, and I'm cruising at high speed. But it was, so I didn't think much of it. Well, about 45 minutes into the drive, the car loses all power on the highway, and dies. Now I'm fucking shitting bricks thinking I just blew a head gasket. It wasn't that hot, and not overheating, but it was the only thing I could think of. I restarted it, and it ran for about 2 seconds before the same thing happened. I gave it about 15 minutes, and it ran for about 10 seconds before it happened again. I'm thinking my head gaskets are gone, so I decide to let it go, and call my Dad for a tow. When he gets here I try once more, and notice the fuel pump sounds like shit, and it still won't run. We tow it up to the house.

Once there, I look everything over, change the oil (Been needing to do that), and add coolant (It was a little low). This probably took about 2-3 hours because I have ADD, then I started it up. Started, ran perfect, took it for a drive, and everything was perfect. My guess was that I was vaporizing the fuel to, but I'm not sure how. It was hot out, but the fuel lines run through a fairly cool part of my engine compartment, off to the passenger side of the motor. And they never run closer than 3" from the motor, until they go to the rail of course. So I'm not sure how it was happening, but it was. I'm willing to forgive the Walbro pumps for being louder than a fucking airplane, because they do the job, but this I can't really put up with.
88GT 3.4 DOHC Turbo
Gooch wrote:Way to go douche. You are like a one-man, fiero-destroying machine.
The Dark Side of Will
Peer Mediator
Posts: 15610
Joined: Wed Nov 24, 2004 11:13 pm
Location: In the darkness, where fear and knowing are one
Contact:

Re: I had a short break-down today. Kind of interesting story.

Post by The Dark Side of Will »

Interesting... The Mule is running a Corvette pump and I've done 16 hour drives with it without this problem at all. It gets pretty darn warm. The center tunnel gets outright hot.
User avatar
Shaun41178(2)
Posts: 8358
Joined: Fri Nov 19, 2004 7:12 pm
Location: Ben Phelps is an alleged scammer

Re: I had a short break-down today. Kind of interesting story.

Post by Shaun41178(2) »

I have put 15 hours nonstop on my walbro but the outside temps weren't all that high. just saying.
FieroPhrek working on that ls4 swap for 18 years and counting now. 18 years!!!!! LOL

530 whp is greater than 312
User avatar
Aaron
I just wanna ride my motorcycle
Posts: 5957
Joined: Sun May 29, 2005 5:15 am
Contact:

Re: I had a short break-down today. Kind of interesting story.

Post by Aaron »

That's the weird part, I too have done far longer, and far more demanding things to my fuel pump without any issues. I'm not sure why it all the sudden did it, or what caused it. I has at highway speeds, about 45 minutes into the trip, at temperatures not that high really, off boost, at low engine RPM and loads. Just decided that was the day I guess.
88GT 3.4 DOHC Turbo
Gooch wrote:Way to go douche. You are like a one-man, fiero-destroying machine.
AkursedX
Turbo-boostin!
Posts: 1078
Joined: Wed Nov 17, 2004 2:14 pm
Location: Lackawanna, NY

Re: I had a short break-down today. Kind of interesting story.

Post by AkursedX »

I don't know how concerned I am about this issue. The conditions that the car was in was very out of the ordinary and very extreme. I can't even say for 100%certainty that the pump was causing the issue and not the extreme heat. I have an authentic walbro pump. I must say that I like John's bosch pump setup. A fuel cooler might not be a bad idea either. I will probably consult with Ryan and discuss a potential fix, if I even feel that it's needed.
'88 Fiero GT- 3800 Turbo Best E.T. 11.36 Best MPH 121.50 (Sold and gone)
2021 Hyundai Veloster-N (SCCA Solo D-Street)
2004 Mazda RX-8 (SCCA Solo STX)
WNY SCCA-Region Auto-X Program Chair
The Dark Side of Will
Peer Mediator
Posts: 15610
Joined: Wed Nov 24, 2004 11:13 pm
Location: In the darkness, where fear and knowing are one
Contact:

Re: I had a short break-down today. Kind of interesting story.

Post by The Dark Side of Will »

If the fuel temp has something to do with it, then moving the pressure regulator down by the tank so that the return flow doesn't get heated by the engine would help.

I thought that GM originally used looped fuel systems to help avoid vapor lock when restarting a very heat soaked car, but now that they use returnless fuel systems, I wonder why they ever used the looped systems.
AkursedX
Turbo-boostin!
Posts: 1078
Joined: Wed Nov 17, 2004 2:14 pm
Location: Lackawanna, NY

Re: I had a short break-down today. Kind of interesting story.

Post by AkursedX »

The Dark Side of Will wrote:If the fuel temp has something to do with it, then moving the pressure regulator down by the tank so that the return flow doesn't get heated by the engine would help.

I thought that GM originally used looped fuel systems to help avoid vapor lock when restarting a very heat soaked car, but now that they use returnless fuel systems, I wonder why they ever used the looped systems.
My old supercharged setup utilized a returnless setup. I never had any issues with that setup and I did a loop of the dream cruise last year as well. Since I am running a camaro intake on the turbo setup, I had to go back to a return setup since we couldn't adapt the fuel rails over.
'88 Fiero GT- 3800 Turbo Best E.T. 11.36 Best MPH 121.50 (Sold and gone)
2021 Hyundai Veloster-N (SCCA Solo D-Street)
2004 Mazda RX-8 (SCCA Solo STX)
WNY SCCA-Region Auto-X Program Chair
fieroguru
Posts: 258
Joined: Sun Jan 15, 2006 1:30 pm

Re: I had a short break-down today. Kind of interesting story.

Post by fieroguru »

My 4.3 CPI fuel pump was noisy from day one and on long runs - about 275 miles of continuous running the fuel pump would momentarily quit. Before the car cam to a stop, it could be restarted. At the early stages it would run for another hour or two. Then over time it took less and less. Then it started acting up on my return commute from work in the afternoon sun. If I felt it acting up, filling with cool gas fixed it for a while...

Eventually I pulled it for the LT1 vette pump that has been wisper quiet and never acted up since (and my mpg has improved by 2mpg - hotter ambient temps).
The Dark Side of Will
Peer Mediator
Posts: 15610
Joined: Wed Nov 24, 2004 11:13 pm
Location: In the darkness, where fear and knowing are one
Contact:

Re: I had a short break-down today. Kind of interesting story.

Post by The Dark Side of Will »

AkursedX wrote:
The Dark Side of Will wrote:If the fuel temp has something to do with it, then moving the pressure regulator down by the tank so that the return flow doesn't get heated by the engine would help.

I thought that GM originally used looped fuel systems to help avoid vapor lock when restarting a very heat soaked car, but now that they use returnless fuel systems, I wonder why they ever used the looped systems.
My old supercharged setup utilized a returnless setup. I never had any issues with that setup and I did a loop of the dream cruise last year as well. Since I am running a camaro intake on the turbo setup, I had to go back to a return setup since we couldn't adapt the fuel rails over.
If you move the FPR from the fuel rail to the firewall, you get close to a returnless fuel system. The closer you mount the FPR to the tank, the less fuel heating you'll have. You should be able to do this with the stock fuel rail for the Camaro intake and an aftermarket regulator.
Sinister Fiero
Posts: 665
Joined: Tue Jun 07, 2005 12:10 pm
Location: Waterloo, Indiana
Contact:

Re: I had a short break-down today. Kind of interesting story.

Post by Sinister Fiero »

The stock Fiero fuel system has a design flaw in the tank. The sending unit in the tank is designed so the return fuel (from the rail) dumps into the bottom of the tank right next to the pickup sock for the fuel pump. It is very possible that Joe's fuel got so hot that the fuel started vaporizing in the return line. When this happened, it started pushing air bubbles right into the bottom of the tank right next to the pickup sock. The pump started taking in these bubbles which created a loss of output capacity (since these pumps are not designed to pump air).

The fuel rail we used on Joe's car (F-body L36) is as close to a "returnless" system as you can get while still having the return line and regulator mounted on the rail. The regulator and return line tap into the supply side right at the point where the fuel supply line comes in vs. having the entire fuel supply circulate thru the rails over all injectors before making it to the regulator like the L67 and FWD L36 designs. So moving the regulator and return line off the rail may not help this situation much; but it is certainly possible it would reduce fuel temps some.

Installing a set of aftermarket aluminum fuel logs (configured returnless) might help the vaporization issue that Joe experienced. However, the larger aluminum logs would heat soak the fuel more in the rails vs. the smaller steel rails Joe is using now which could create other problems.

I have three suggested fixes:

1) Run a full tank or near full tank of fuel on hot days.
-or-
2) Install a fuel cooler.
-or-
3) Modify the fuel sending unit in the tank so (hot) return fuel can no longer dump below and next to the pickup sock for the fuel pump. Unfortunately this will require you to install a new fuel pump support bracket since the fuel pump is currently supported by the return line (stock configuration).
OVERKILL IS UNDERRATED
Image
Custom GM OBD1 & OBD2 Tuning | Engine Conversions | www.gmtuners.com
befarrer
Posts: 1085
Joined: Mon Feb 20, 2006 12:18 am
Location: Alberta

Re: I had a short break-down today. Kind of interesting story.

Post by befarrer »

I have had something simmialr. A few weeks ago I was autocrossing and it was about 32C outside, car ran fine, but when I started it up about 20 minutes later, I could hear my fuel pump making loud noises, and the engine stumbling when it was doing that. It cleared up after about 10 seconds. I am running SS braided lines and a stock Quad 4 fuel rail and regulator, which is a return setup. All I can think of it that the heat from the motor was vapourizing the fuel in the lines. The thing about it sucking up the vaporized fuel from the return line can explain this, so that is plausable,
The Dark Side of Will
Peer Mediator
Posts: 15610
Joined: Wed Nov 24, 2004 11:13 pm
Location: In the darkness, where fear and knowing are one
Contact:

Re: I had a short break-down today. Kind of interesting story.

Post by The Dark Side of Will »

Sinister Fiero wrote:The regulator and return line tap into the supply side right at the point where the fuel supply line comes in vs. having the entire fuel supply circulate thru the rails over all injectors before making it to the regulator like the L67 and FWD L36 designs. So moving the regulator and return line off the rail may not help this situation much; but it is certainly possible it would reduce fuel temps some.
This is the way the new SS fuel rails for the Northstar are made.
Since the fuel tubing is going to get up to engine compartment temps in heat soak conditions, the shorter the length of tubing from the tank to the regulator and back, the less heat the fuel is going to pick up.

Also, phenolic spacers/insulators between the fuel rail and an aluminum manifold may help as well, but require machine work to install correctly.
User avatar
Emc209i
Posts: 1466
Joined: Thu Jan 18, 2007 2:31 am
Location: Charleston, SC

Re: I had a short break-down today. Kind of interesting story.

Post by Emc209i »

Aaron wrote:That's the weird part, I too have done far longer, and far more demanding things to my fuel pump without any issues. I'm not sure why it all the sudden did it, or what caused it. I has at highway speeds, about 45 minutes into the trip, at temperatures not that high really, off boost, at low engine RPM and loads. Just decided that was the day I guess.

Hmm, weird. Could have sworn your name was on that text message about a 6,000 mile Walbro failure. Must be losing my mind.
User avatar
Aaron
I just wanna ride my motorcycle
Posts: 5957
Joined: Sun May 29, 2005 5:15 am
Contact:

Re: I had a short break-down today. Kind of interesting story.

Post by Aaron »

Did it ever cross your mind that the above stated incident, and the one you're thinking of, are one in the same? Or that my initial thought was that it was the fuel pump? But after looking into it further, decided it was the fuel instead? Seems pretty plausible to me....Stuck on the side of the road, fuel pump making some really godawful noises....Sounds like a fuel pump to me. I wouldn't say you're losing your mind, just fucking stupid, that's all.
88GT 3.4 DOHC Turbo
Gooch wrote:Way to go douche. You are like a one-man, fiero-destroying machine.
AkursedX
Turbo-boostin!
Posts: 1078
Joined: Wed Nov 17, 2004 2:14 pm
Location: Lackawanna, NY

Re: I had a short break-down today. Kind of interesting story.

Post by AkursedX »

Well a short update. I let the car sit for a few days and took it out again. I am now leaning out under boost. After checking out a few things, I more than likely damaged the fuel pump in this incident. Bleh.
'88 Fiero GT- 3800 Turbo Best E.T. 11.36 Best MPH 121.50 (Sold and gone)
2021 Hyundai Veloster-N (SCCA Solo D-Street)
2004 Mazda RX-8 (SCCA Solo STX)
WNY SCCA-Region Auto-X Program Chair
Sinister Fiero
Posts: 665
Joined: Tue Jun 07, 2005 12:10 pm
Location: Waterloo, Indiana
Contact:

Re: I had a short break-down today. Kind of interesting story.

Post by Sinister Fiero »

Very possible. The walbro uses metal gears that mesh for the pump mechanism and they rely on the fuel to lubricate and cool them. If they were starved of fuel, it is possible they suffered premature wear or damage which could result in reduced output. Best thing to do is a brief WOT fuel pressure/flow test using a pressure gauge to see if the fuel pressure is dropping off during boost operation.

On a side note, I think I have come up with a way to modify the stock Fiero sending unit so the return fuel will be diverted from traveling down to under the pickup sock and instead have it dump upstream (shortly after coming into the tank) from above WITHOUT needing to add a new support bracket for the pump.
Post Reply