Distributor priming fuel pump?

[TYTILIDIE]

If you h ad your key on, and did nothing else but turn the distributor and the fuel pump primed, what would you think?

 

[MRKING]

Re: Distributor priming fuel pump?

If you mean the key on and with a loose dist holddown , you can turn the dist some and hear the fp prime ? I dont know why but i have had the same thing happen to me .

 

[WyoSyclone]

Re: Distributor priming fuel pump?

maybe you went past the trigger on the dizzy and fired the injectors, requiring the pump to bring the pressure back up?

 

[SY2932]

Re: Distributor priming fuel pump?

maybe you went past the trigger on the dizzy and fired the injectors, requiring the pump to bring the pressure back up?

X2. You generated a reference pulse and the ECM thought that you were trying to start the truck. DaveP post here.

 

[Big Mike]

Re: Distributor priming fuel pump?

You built oil pressure and it signaled the ecm to turn fuel pump on like the truck was running. When you first turn your key you should hear the fuel pump prime too.

 

[TYTILIDIE]

Re: Distributor priming fuel pump?

This is very interesting and I have never noticed this before. We got the truck to start finally., I hooked up datamster and had a code 34 low MAP. We swapped mine into his and the damn thing fired right up after fighting it for 3 days. Not sure what that was all about because the map sensor is brand new and fired my truck right up. I am going to spend the next week working out those bugs.

One thing in reference to spark, timing etc. We went to set timing (yes I disconnected the tan wire) and the mark wasn't there with the timing light. I am going to double check that the distributor isn't a tooth off but it was really weird.

 

[Don W.]

Re: Distributor priming fuel pump?

The "tooth off" thing is often misunderstood when it comes to whether the timing can be set or not. There are 13 teeth on the distributor. 1 tooth = 28º of distributor body, or 56º of crankshaft rotation.

First, theoretically it does not matter "where" the shaft is indexed to the cam. It can be on any of the 13 positions. Theoretically you turn the body of the distributor, until the rotor lines up with #1 in the cap, and it will run. The important thing is the correlation between the shaft and the body. The 'firing' and the rotor-to-cap.

But here's why it's an issue. There are connectors on the body. They do not permit the body to be rotated at will. Sometimes, if it is a "tooth off", you just can't physically turn the body enough to get the timing correct. Or the body isn't where you want it to be when the timing IS set. In this case moving a tooth or more, will correct it.

X2 I've been trying to figure out how to say this for years and now Ty0331 has done it. Thanks! :tup:
I would only add that doing the above you can end up with #1 anywhere on the cap and it doesn't matter. As long as each cyl gets its spark at the correct time it makes no difference which terminal it came from on the dist.

 

[turboj91]

Re: Distributor priming fuel pump?

There is one [common] engine that it DOES matter that the #1 cyl be on the correct #1 position on the cap, and it is very important that this be done for the longevity of the engine. Anyone want to take a stab at the "what engine / why" ?

Hint: This engine has not been available in North America since 1979. But it was used in Millions of vehichles world wide.

I'll take a stab at this engine. Does its North American demise have to do with emissions (not being able to make the standards for 1980)?

 

[TYTILIDIE]

Re: Distributor priming fuel pump?

With the tan wire disconnected, shouldn't I see 0 timing in datamaster? Or would I see what the computer wants? Funny you mentioned a tooth off is 28*, that was the #I saw in datamaster. So it is safe to say I should try and move the tooth back. I understand the theory about timing and where the rotor should be and all that. I do not however, understand how the engine can run so perfect and the balancer mark not show up.

 

[Don W.]

Re: Distributor priming fuel pump?

1st choice: Volkswagen. The spark was retarded slightly within the distributor for #3 cyl. Why? Number 3 always ran hot because it's airflow was partially blocked by the oil cooler. Retarding the timing a bit on that one cyl was VW's cheap fix.

Gets weird from here.

John Deer 2cly tractor. An inline odd fire two cyl engine

HD motorcycle essentially an odd fire V2

May be more, as there is always an exception to the rule.

 

[turboj91]

Re: Distributor priming fuel pump?

Yes.[/QUOTE]

And would this engine happen to be air cooled?

 

[Don W.]

Re: Distributor priming fuel pump?

Yes.

And would this engine happen to be air cooled?[/quote]

Did you see my post above? :lol:

 

[turboj91]

Re: Distributor priming fuel pump?

And would this engine happen to be air cooled?

Did you see my post above? :lol:[/QUOTE]

Yes I did but I only read the first 3 words. Never got past VW. I knew what it was from my first post and I was just playing with Dave. I have now read your entire explaination. IIRC, doesn't that engine also have the balancer timing mark for 1 & 3 come "up" at the same time therefor making it very important to have the #1 proper so the #3 doesn't have the advance of #1 and then run hot because of the blocked airflow.

I'll let this get back on topic after Dave gives up our prizes.

 

[Don W.]

Re: Distributor priming fuel pump?

I think you should win because I had to do a bit of Googling but as soon as I saw Vdub I knew what it was. No clue on the timing mark. Now back to our regularly scheduled program.