Very odd thing happened today

torresmd · 02-25-2009, 09:16 AM

I was driving home from work today on freeway in 4th gear, cruising at about 70mph and suddenly lost power for about 4 seconds. It felt like I ran out of gas but no sputtering just total loss of power. I was just coasting. I down shifted to 3rd gave it some gas and the car felt normal again. I kept going on the freeway all the way home for another 8-10 miles and the car felt totally normal. What in the world could have happened. I did fill up yesterday a new tank of gas. Bad gas? Something more serious? I just don't want to be stranded suddenly on the freeway tonight going home.
Thanks!

timc · 02-25-2009, 09:24 AM

I had that happen to me several times, turned out to be the Yellow relay located in the engine compartment Fuse/Relay panel. The solder joints go bad.

Chuck Jones · 09:30 AM

Sounds more of an electronic issue than a gas one. Gas would have sputtered...but an electrical issue would kill it dead instantly.....I had this happen one time in the 930 and it ended up being the CDI box. I installed an MSD 6AL CDI box and used the included rev limiter to cut off at 6500 rpm. No problem since then. The yellow fuel pump relay in the rear left side of your engine compartment is also a potential problem area. I had several cut outs like you mentioned, and the indy found a broken connection in the socket under the yellow relay. The electrical gremlins are the worst things to try to chase down because you have to catch them as they are occuring in order to focus in on the correct part or connection. Your car went back to "normal" which means that it's going to take a few more incidents to get to the meat of the matter....UNLESS you're a whiz with a voltmeter and can chase circuitry....I dont' have that sort of expertise...so I pay to have the problem resolved.

equality72521 · 02-25-2009, 09:33 AM

Quote:

Originally Posted by timc

I had that happen to me several times, turned out to be the Yellow relay located in the engine compartment Fuse/Relay panel. The solder joints go bad.

Same here, except mine is an earlier car that used the red one. This happened a couple of times and then finally just quit. I put a spare fuel pump relay in to get me home and it ran fine. I replaced the relay with the approprite one and it hasn't happened since.

mark houghton · 02-25-2009, 09:58 AM

Quote:

Originally Posted by equality72521

Same here, except mine is an earlier car that used the red one. This happened a couple of times and then finally just quit. I put a spare fuel pump relay in to get me home and it ran fine. I replaced the relay with the approprite one and it hasn't happened since.

Ditto ditto...except it's only happend to me twice and both times either after parking or sitting in the driveway, then attempting to start her back up. Both times I just pulled the relay out, pursed my lips and gave it a good blow and gently licked the prongs, stuck her back in and off we went. One of these days it will probably strand me.
So one of the fuel pump relays will stick in there and do for emergency substitutions??? I never thought of that.

torresmd · 02-25-2009, 10:07 AM

Maybe I should buy a fuel pump relay and keep it in the car just in case. I hate to be stranded especially at 6am on the freeway. Where do I purchase a fuel pump relay. I will start there and hope for the best.

equality72521 · 02-25-2009, 10:10 AM

Quote:

Originally Posted by mark houghton

Ditto ditto...except it's only happend to me twice and both times either after parking or sitting in the driveway, then attempting to start her back up. Both times I just pulled the relay out, pursed my lips and gave it a good blow and gently licked the prongs, stuck her back in and off we went. One of these days it will probably strand me.
So one of the fuel pump relays will stick in there and do for emergency substitutions??? I never thought of that.

Yep, I had an extra red fuel pump relay and ran it for a couple of weeks until I got the replacement. I would be driving along and the engine would just quit. No sputtering or anything. Just died. I would restart and it would work fine for a while. Eventually it just wouldn't start anymore. When I pulled the relay it was hot so I imagine the contacts were bad and causing high resistance. The replacement stays cool.

equality72521 · 10:14 AM

Quote:

Originally Posted by torresmd

Maybe I should buy a fuel pump relay and keep it in the car just in case. I hate to be stranded especially at 6am on the freeway. Where do I purchase a fuel pump relay. I will start there and hope for the best.

You can buy the relays here. The yellow one is pricey so if you want a spare for emergency I'd go for a standard red fuel pump relay. Many have dismantled the yellow relay only to find a bad solder connection as timc mentioned above. Try that before buying a new one.

torresmd · 02-25-2009, 10:37 AM

Thanks guys.... Love this forum!

mark houghton · 02-25-2009, 10:47 AM

Quote:

Originally Posted by equality72521

You can buy the relays here. The yellow one is pricey so if you want a spare for emergency I'd go for a standard red fuel pump relay. Many have dismantled the yellow relay only to find a bad solder connection as timc mentioned above. Try that before buying a new one.

I've been meaning to pull mine apart for a couple years now, just to inspect/clean/repair. That, vs. the cost of a new one is a bargain in my mind.
Now for the stupid question: I continually get confused on the purpose of the "yellow"relay - knowing that I have a 50/50 chance of getting it right. Overboost cut-out relay, or ignition time delay run-on relay? If I remember correctly, both relays act by cutting off the fuel pumps, but for different reasons.

torresmd · 02-25-2009, 10:51 AM

Hmmm.... where exactly are these relays located. I have been peering into the engine bay for a while now and no luck. I also searched for the relay in pelican parts, cannot seem to find them. I see other relays but none for fuel pump.

mark houghton · 02-25-2009, 10:57 AM

Quote:

Originally Posted by Chuck Jones

The electrical gremlins are the worst things to try to chase down because you have to catch them as they are occuring in order to focus in on the correct part or connection

You got that right, Chuck. I can remember many years ago when my wife owned and drove a rusted out Jaguar sedan in the Chicago area. It would mysteriously die at the most inopportune times....and would not re-start until cooling down completely. Logic told me it had to be some damn sensor or another that was failing when it got too hot, but I never had my trusty VOM meter with me until one day....as luck would have it....it died as we were backing out of the driveway. Ah-HA, you bastard! (I said), finally we're dead at home with all my tools available. I had already narrowed it down to a couple of possibilities and had it nailed in less than a minute. $20 later with a new part and we never saw that problem again. We spent much more than that having the thing towed home beforehand.

equality72521 · 02-25-2009, 11:03 AM

Quote:

Originally Posted by torresmd

Hmmm.... where exactly are these relays located. I have been peering into the engine bay for a while now and no luck. I also searched for the relay in pelican parts, cannot seem to find them. I see other relays but none for fuel pump.

The fuel pump relays are in the front fuse/relay panel. The yellow one is the boost/air meter relay in the engine compartment and is either a yellow rectangular relay or a black or red round relay.

equality72521 · 02-25-2009, 11:05 AM

Boost/air meter relay and fuel pump relays are here: http://www.pelicanparts.com/catalog/shopcart/911M/POR_911M_ELchrg_pg3.htm#item20

Miguel Antonett · 02-25-2009, 11:11 AM

Ditto ditto on the relay. I keep a spare, as well as fuses.

You will have to remove the cover located on the driver side of the engine compartment facing the intercooler.

A930Rocket · 02-25-2009, 06:26 PM

I've mentioned it before, but I'll say it again. I removed all the variables of the flapper switch, over boost switch, yellow relay, Mars lining up with Jupiter, etc. by grounding the fuel pump relays up front with an inertia swith. That what all those do in back. If all is in order, it grounds the system and lets the fuel pump relays kick in. If I have an impact, the switch cuts off the fuel.

DDDD · 02-26-2009, 04:53 AM

Quote:

Originally Posted by A930Rocket

I've mentioned it before, but I'll say it again. I removed all the variables of the flapper switch, over boost switch, yellow relay, Mars lining up with Jupiter, etc. by grounding the fuel pump relays up front with an inertia swith. That what all those do in back. If all is in order, it grounds the system and lets the fuel pump relays kick in. If I have an impact, the switch cuts off the fuel.

Nice!

mark houghton · 02-26-2009, 04:56 AM

Quote:

Originally Posted by A930Rocket

I've mentioned it before, but I'll say it again. I removed all the variables of the flapper switch, over boost switch, yellow relay, Mars lining up with Jupiter, etc. by grounding the fuel pump relays up front with an inertia swith. That what all those do in back. If all is in order, it grounds the system and lets the fuel pump relays kick in. If I have an impact, the switch cuts off the fuel.

One word...SIMPLICITY (and dependability). As long as you're confident that overboost situations won't ever develop necessitating that funky OB safety mechanism's original purpose. Sounds like a good tradeoff. Keep an eye on the boost, vs. having any one of those relays or switches strand you miles from home.