Advice needed...car keeps vapor locking at Okteenerfest Options

[pbanders]

I used to have a 2.2L with Webers and a Facet pump in my car, had issues with vapor lock all the time. After I converted to D-Jet FI, I have <never> had the car vapor lock, despite living in AZ and driving in ungodly heat. My pump is in the engine compartment and I don't have deflectors. I'm bringing this up because I'm wondering if many case of vapor lock, or what appears to be vapor lock, are actually pump issues or some other problem. Food for thought.

[mepstein]

This will help
Powdercoated and pretty.
(IMG:style_emoticons/default/smile.gif)

[saigon71]

It was a little scary having my engine quit on the mountain passes during the Okteenerfest drive last year. I had to abort the drive early. (IMG:style_emoticons/default/sad.gif) It also happened on a regular basis in the hot weather while driving around town. More than once, I've pushed the car off the road due to what I believe to be vapor lock. Moving the fuel pump up front was near the top of my to-do list this winter.

My original plan was to move the pump above the pan that covers the steering rack as many have done, so I bought the "fuel pump relocation kit" from AA. I liked the idea of not cutting an additional hole in my car. After messing around with it for a while, I realized I'd rather cut the hole in the front trunk bulk head and install the pump in the 75-76 location.

A huge thanks to Mark (Mepstein) and Kevin (Okieflier) to donating the fuel pump blister parts. I continue to be amazed by the kindness of folks on this forum. (IMG:style_emoticons/default/beerchug.gif)

The first step was removing the old fuel pump and engine compartment lines. To fill the old fuel pump mounting holes, I picked up some 1/4" plugs at Lowes and installed them with Permatex:





Then I ran the 14 GA wire from the original fuel pump leads, through the tunnel and up through the factory grommet in the front trunk bulkhead. I didn't want to drill another hole in the firewall, so I snuck the wires into the same hole as the new odometer cable. The wires were zip-tied to the factory wiring all the way up. I decided to solder the wires and use heat shrink. I added a piece of heat shrink for anti-chafing measures where the wires enter the firewall:









Time to cut the hole. I used the 75-76 cover as a template, measured in 1/2" from the edge and cut the hole with a die grinder. For fasteners, I went with spring steel clip-on nuts and machine screws:





Ran the FI hose in the engine bay:





I needed some adapters up front to get from the 3/8" tank supply line down to 5/16" for the fuel filter, then to 3/8" for the large center tunnel line. These brass fittings from ACE hardware worked well:



Mounted the fuel pump for a test fit:





Ran all the hoses up front and connected the wires, leaving plenty of slack to perform maintenance on the pump and/or filter:







I'm looking forward to the next driving season. I hope this gets eliminates the vapor lock issue of an otherwise very reliable car.

[ndfrigi]

wow nicely done! Good job sir!

[Bartlett 914]

I am all for moving the pump to the front.

I sometimes wonder if these issues are from a starved pump. If the tank is not getting air to displace the used fuel, the pump may run dry. The pump needs gas through it to keep it cool. Loosen the gas cap is a good way to see if this is an issue.

[Olympic 914]

So you pulled your engine out. Doing anything else?

[mepstein]

I am all for moving the pump to the front.

I sometimes wonder if these issues are from a starved pump. If the tank is not getting air to displace the used fuel, the pump may run dry. The pump needs gas through it to keep it cool. Loosen the gas cap is a good way to see if this is an issue.

I don't think that is Bob's issue. He drove 7 hours to the event. I was in the car with him during the drive at the event. Not only was the day heating up but most of the times the car stalled, we were going slow and uphill. I think almost every time. The first time was pulling into town for lunch. We stalled it into the parking spot. At that point, we could let the car cool. The next time was a slow uphill through traffic, we were able to borrow a water spray bottle and that let us cool down the pump very quickly. The next time was another uphill and a couple hits from the water bottle got us going quickly. Previously, Bob used to have to wait 45 minutes to get going again. Once the engine was heat soaked, it didn't stay running long, especially when we slowed down. It doesn't seem to happen to him once the weather turns cool. I would be surprised if this doesn't fix the issue.
The day we left, it was cool and I believe Bob drove home without issue. I think the airflow at 75mph also helped.

If it doesn't, we'll just have to drop in a six.

[JFJ914]

The intermittent fuel pump that kept my 914 home from Okteenerfest turned out to be a bad relay plate. All relays worked but no volts at the 14 pin plug to the pump.

[mepstein]

The intermittent fuel pump that kept my 914 home from Okteenerfest turned out to be a bad relay plate. All relays worked but no volts at the 14 pin plug to the pump.

Exact same thing happened to me. Took a while to figure out. When I finally did, I switched in a different one and the car started right up.

[Bartlett 914]

I am all for moving the pump to the front.

I sometimes wonder if these issues are from a starved pump. If the tank is not getting air to displace the used fuel, the pump may run dry. The pump needs gas through it to keep it cool. Loosen the gas cap is a good way to see if this is an issue.

I don't think that is Bob's issue. He drove 7 hours to the event. I was in the car with him during the drive at the event. Not only was the day heating up but most of the times the car stalled, we were going slow and uphill. I think almost every time. The first time was pulling into town for lunch. We stalled it into the parking spot. At that point, we could let the car cool. The next time was a slow uphill through traffic, we were able to borrow a water spray bottle and that let us cool down the pump very quickly. The next time was another uphill and a couple hits from the water bottle got us going quickly. Previously, Bob used to have to wait 45 minutes to get going again. Once the engine was heat soaked, it didn't stay running long, especially when we slowed down. It doesn't seem to happen to him once the weather turns cool. I would be surprised if this doesn't fix the issue.
The day we left, it was cool and I believe Bob drove home without issue. I think the airflow at 75mph also helped.

If it doesn't, we'll just have to drop in a six.

You may be right. I was only putting thoughts out there. The pump over heats. In a late car, the pump is behind a cover in an enclosed area and it does not over heat. This leaves me with 3 thoughts. Low fuel volume, defective pump or an external source of the heat. Maybe the flapper valve exhaust vent from the heat exchangers is doing this.

[sechszylinder]

Another reason for hot start issues could be leaking fuel injectors. After shutting down the engine, they leak fuel into the cylinders which results in an extreme rich AFR, which prevents the engine from starting. After lots of cranking, the excess amount of fuel is gone, AFR is right and the engine starts again.
Unfortunately relocating the fuel pump does not fix this problem.

Don't ask me how I know ;-)

BR
Benno

[saigon71]

So you pulled your engine out. Doing anything else?

Unfortunately, yes.

I had a very slight oil leak, so I re-sealed the oil pump and installed another rear main seal. Frustrating after a rebuild last winter.

Additionally, my transmission input shaft seal went bad, spraying transmission on the brand new sachs clutch disc, causing it to slip and wear out prematurely. Gonna bang in a new input shaft seal, clutch and shim the pivot fork ball.

[saigon71]

Like Mark said, the car fired up immediately after spraying the fuel pump down with water. I'd be surprised if moving the fuel pump up front didn't fix this problem. If it doesn't, I can eliminate one potential cause.

It seemed like once the car vapor-locked a few times with a new fuel pump, it was much more prone to happen again. I wonder if the pump gets weaker from trying to pump vapor?

Can't wait to get it back together and go for a spin. (IMG:style_emoticons/default/driving.gif)

[mepstein]

Like Mark said, the car fired up immediately after spraying the fuel pump down with water. I'd be surprised if moving the fuel pump up front didn't fix this problem. If it doesn't, I can eliminate one potential cause.

It seemed like once the car vapor-locked a few times with a new fuel pump, it was much more prone to happen again. I wonder if the pump gets weaker from trying to pump vapor?

Can't wait to get it back together and go for a spin. (IMG:style_emoticons/default/driving.gif)

I think once the engine and surrounding area was heat soaked, it was just a matter of time. I thought we were ok once we cut the ride short and headed back to the motel. I think keeping the speed up and getting airflow made a difference. I'm pretty sure that every time it died, we were moving slowly. I don't think the pump will ever get hot in the forward location.