fuel injection pressure wierdness...

[Dave WM]

I did check the CSV as you described early on, I also clamped the line off to it on this latest go round where the pressure would suddenly drop to see if that was a source of the loss of pressure (was not still dropped to zero in less than a min). I went ahead and ordered a new filter and will replace the pre filter between the pump and tank just to eliminate that as a possible issue. The thing that really gets me was when it was not pumping up to full pressure quickly was the same time it would drop off quickly. That would have to be a massive leak to account for if the pump was working as it should. I will go start in in a few min and see what happens, I suspect it will be fine again since last nite the pressure started working normally again.

[Dave WM]

9;20 am 70f started right up, pressures all look normal.

boy this will drive you crazy...

Back to the plan,

1. disconnect fuel line at inlet of fuel filter, run pump see if any junk comes out
2. reverse filter flow flush with same line, see what comes out of filter
3. replace clear pre filter (I can see some junk, not a lot).
4. replace main filter.

One reason I am not focusing on the FPR is when the pressure was acting up, clamping the return did not change anything. Also when I had the rail off for injector testing there was NO leakage from the injectors OR the vacuum line that goes to the FPR.

 

 

Edited December 2, 2016 by Dave WM

[Dave WM]

ok there is def junk in the lines... But I don't think that is the real issue. I think the pump may not be getting full voltage, perhaps a 2.0v drop is normal but I did notice some odd clicking sounds like the relay was not really working right, and it would sound different, sometimes more than one click, some times one solid click and then good pressure.

I am starting to wonder if there is an issue with the electrical supply to the pump.

I have 12.2 volt at the battery (while in the start pos starter solenoid disconnected) and about 10v at the pump. Also odd is the voltage rises the longer the key is turned, I would have thought it would be the other way if at all as the pressure builds. The click I am hearing related to the "start" is under the hood, sounds like forward of the voltage regulator. Again it sometimes is a single click then other times several clicks. On to the FSM

Duh it was the cold start valve I was hearing. It was prob cycling off from the internal heater.

I am just going to replace the filters and be done with it before I break something. I guess a 2 v drop is not excessive considering the wire/connections/relays.

 

 

Edited December 2, 2016 by Dave WM

[Zed Head]

Maybe it just needs a good thrashing.  

[Dave WM]

hmm more thought re the odd behavior, I noted above, the lack of full pressure may have been the CSV after all, prior poster brought this up. That would explain a lot.

the pressure starts out low while the CSV is firing, the internal heater turns it off, I hear a bunch of clicking then suddenly the pressure comes up after the CSV shuts off (all this is during the test cycle of the pump starter solenoid off). So the massive leak was indeed the CSV. I thought I had clamped it off, maybe missed something.

Sorry about all the red herrings.

[Dave WM]

18 minutes ago, Zed Head said:

Maybe it just needs a good thrashing.  

thanks man I needed that. show it who is boss...

[Zed Head]

I never really thought about the CSV action when testing the fuel pressure.  You're saying that the disconnecting the starter solenoid to test pressure, but with the CSV still connected, and engine cold, allows the CSV to dump fuel when testing?  Dang, all these years of incomplete advice,  I feel bad.  Your CSV must allow a lot of fuel though, to get a pressure drop.  How long does it take to build pressure from zero?

Plus all of that fuel probably sat in your intake manifold all night, giving you the quick start the next day.

[Dave WM]

pretty quick you can hear it clicking jumps from about 45 to about 55 with the return clamped off, this is when I was thinking there was something wrong with the pump. It all happens in seconds but since it would happen sometimes (cold eng) and not others (just warm enough to not activate) it would behave different so I thought I had an intermittent issue.

It could be as mentioned before by another poster, maybe I am actually flooding the engine with the warmer thermotime. I figured if that was the case I would have seen lots of black smoke (did not notice any). I think for the next few days I will see how the car starts with the thermotime unplugged, weather forecast has low 80's for a while.

to answer your question, yes disconnect the starter solenoid and use the "start" pos to activate the pump was  also firing the CSV. So if you want to use this method best to unplug it. The random clicking under the hood was confusing me.

Edited December 2, 2016 by Dave WM

[EuroDat]

Hi Dave, Im with Zed Head on giving incorrect advice. Never accured to me the csv would fire just on the starter function. I thought it needed AFM or oil presure to activate. I think I might need to read the fsm too 

I replaced all my fuel lines with new rubber and used a rubber line the the csv so I could test it when I was looking for my leak down. that way I could clamp it shut with vice grips and two pieces of aluminium strip. My leakdown was in the check valve in the fuel pump.

Your problem would frustrate the crape out of me. Nothing worse then problems that come and go. I have a problem with my ECU. I have three of them, but they all make the engine run differently, feels different to drive and they all have problems. One works really well and its in the car now, but it starts playing up every now and them. It even left me standed on the side of the road. That is why Im playing with an aftermarket system, just don't have the time to work on it atm.

Goodluck with your search.

[Dave WM]

its been behaving so guess I will just have to live with it for now. I bought a spare ign module to go with my spare fuel pump and 2 spare ECU's