Need some help

[Silverbullet]

My car has always run great, starts right up every time. The last 2 days, it starts cold, runs great, but if I park it to go buy something, and come back it just cranks, no sound of spark. I swapped the wires in back, and it starts, then swap them back, and it runs like normal...So, what is the fix?

Craig

[Michael]

I am assuming you mean the CSV/CPR plug swap?

If so then you have a fuel issue not a spark issue and to be more precise a hot start problem. If it happened quickly, then it's probably easy to diagnose especially if you have been in the engine lately...have you been in the engine lately?

If no, check for lose or broke vacuum lines around the back of the left valve cover where the CPR is. Also check the o rings in the primary pressure regulator. I replace mine about every 2-3 years since it's cheap and easy and hard to tell if they are bad just by looking at them.

Truth us a dozen things can cause a hot start issue, but some quick "dead reckoning/common sense" may zero you in on the culprit quickly with minimal effort.

The "plug swap" forces the CSV to fire no matter what the coolant temp is, so you might start at anything that could cause the fuel mixture to go south. What fuel pump setup are you running?

[Silverbullet]

I have not done anything to the car for like a year, just turn the key and go... I have the new all in one fuel pump, one of the 1st ones like 9 years ago, with new accumulator.

[Michael]

I have not done anything to the car for like a year, just turn the key and go... I have the new all in one fuel pump, one of the 1st ones like 9 years ago, with new accumulator.

I was asking because I thought it might be a failed check valve but if it's a 9 year old pump itself...I wouldn't totally discount that. Probably try to repeat the issue in the shop and check fuel pressures as well as voltage to the pump (rpm relay perhaps?) I'm just throwing out guesses.

[Silverbullet]

I am assuming you mean the CSV/CPR plug swap?

If so then you have a fuel issue not a spark issue and to be more precise a hot start problem. If it happened quickly, then it's probably easy to diagnose especially if you have been in the engine lately...have you been in the engine lately?

If no, check for lose or broke vacuum lines around the back of the left valve cover where the CPR is. Also check the o rings in the primary pressure regulator. I replace mine about every 2-3 years since it's cheap and easy and hard to tell if they are bad just by looking at them.

Truth us a dozen things can cause a hot start issue, but some quick "dead reckoning/common sense" may zero you in on the culprit quickly with minimal effort.

The "plug swap" forces the CSV to fire no matter what the coolant temp is, so you might start at anything that could cause the fuel mixture to go south. What fuel pump setup are you running?

Well, I think you nailed it... I looked and a very small vacuum line pulled had
pulled off, looks like the hose was kind of short, and I didn't have a new hose that small so I put it back on and zip tied it for now, but I will get a longer hose pretty quick.

Thanks,
Craig

[Silverbullet]

I was asking because I thought it might be a failed check valve but if it's a 9 year old pump itself...I wouldn't totally discount that. Probably try to repeat the issue in the shop and check fuel pressures as well as voltage to the pump (rpm relay perhaps?) I'm just throwing out guesses.

I drove it around, let it sit, and it did the crank, no start the 1st time, 2nd time cranking it started... so I started it a few more times, and it took longer than normal to start....
also I remember the 1st all in one fuel pumps had a check valve issue, so a few years ago I installed a in-line check valve at the pump...

Craig

[mark w]

could also be a loss of system pressure when the car is hot- at the primary pressure regulator in the Fuel distributor. if the little seals in there fail, then fuel pressure will bleed off. test fuel pressures and test for residual pressure after shut off, when hot, it should hold for about 30 min.

[Silverbullet]

could also be a loss of system pressure when the car is hot- at the primary pressure regulator in the Fuel distributor. if the little seals in there fail, then fuel pressure will bleed off. test fuel pressures and test for residual pressure after shut off, when hot, it should hold for about 30 min.

Ok,

How is that done? Where do you hook up?

Craig

[Michael]

Ok,

How is that done? Where do you hook up?

Craig

The Primary Pressure Regulator is on the side of the fuel distributor. I think it's a 15mm? It is under sprung pressure so be sure to remove the last few threads by hand and a telescoping magnet wouldn't be a bad idea to get the final piece out.
The O-ring kit is about 10 bucks and can be found at most all of the vendor's sites. Like I said earlier in the thread, it's hard to tell if they are damaged as just a small nick can cause a loss of rest pressure and usually if the rings are old, they are hard and brittle anyway so you destroy them just to check them.

If they are more than 3 or 4 years old or you don't know, just replace them. It's cheap and easy.

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSXoa1EedIIC3kjkj6ytxRW1aco6wzum OeZhg&usqp=CAU

[DMCMW Dave]

The Primary Pressure Regulator is on the side of the fuel distributor. I think it's a 15mm? It is under sprung pressure so be sure to remove the last few threads by hand and a telescoping magnet wouldn't be a bad idea to get the final piece out.
The O-ring kit is about 10 bucks and can be found at most all of the vendor's sites.]

A hint - when you remove and install this, if you have difficulty, remove the banjo bolts on the side of the fuel distributor. Actually you don't have to remove them, just back them off slightly. I've found that sometimes they go so far in they can hang up or nick the small o-ring. (Only one is really a problem but I forget which one.) Removing them all the way also gives you a place to carefully push it out or use compressed air. Don't go crazy with that or you'll be chasing parts all over the garage.

[Michael]

A hint - when you remove and install this, if you have difficulty, remove the banjo bolts on the side of the fuel distributor. Actually you don't have to remove them, just back them off slightly. I've found that sometimes they go so far in they can hang up or nick the small o-ring. (Only one is really a problem but I forget which one.) Removing them all the way also gives you a place to carefully push it out or use compressed air. Don't go crazy with that or you'll be chasing parts all over the garage.

Not to nit pick, but wouldn't new seals be recommended once the banjo bolts have been loosened?

[Ron]

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSXoa1EedIIC3kjkj6ytxRW1aco6wzum OeZhg&usqp=CAU
There is a 3rd o-ring (not shown above) on the push-up valve.
The pin you see inside the spring (above) is part of the push-up valve. The o-ring and another spring are on the other end of it, inside the carrier. You have to push back a retainer to remove a tiny C-clip and remove the carrier plug to replace it.

67401
PPR AT REST:
67400
(See red arrow- The push valve o-ring holds control pressure when the engine is off.)
It does not come in the "hot start o-ring kits", last I knew...:8ball:

[Bitsyncmaster]

There is a 3rd o-ring (not shown above) on the push-up valve.
The pin you see inside the spring (above) is part of the push-up valve. The o-ring and another spring are on the other end of it, inside the carrier. You have to push back a retainer to remove a tiny C-clip and remove the carrier plug to replace it.

67401
PPR AT REST:
67400
(See red arrow- The push valve o-ring holds control pressure when the engine is off.)
It does not come in the "hot start o-ring kits", last I knew...:8ball:

I think the O-ring at the very end of the piston is what seals rest pressure. I don't see what the function of that internal O-ring does.

[Ron]

I think the O-ring at the very end of the piston is what seals rest pressure. I don't see what the function of that internal O-ring does.
Hehe, I thought we were on the same page the last time this came up. Sorry, I'll try again. :smile:

Yes, it seals rest pressure for what would be primary pressure when the engine is running. BUT, there is a metering hole/restrictor passage (see D:01:08, Fig 7) connecting the lower and upper chambers (primary and control pressure) in the FD...
Like I said above, it's holds the control pressure circuit...

More:
"The push valve controls the return of fuel from something called the control-pressure regulator. You'll see more about the control-pressure regulator in 5. Control Systems. For now, all you need to know is that the push valve 0-ring shuts off fuel return from the control-pressure regulator to better maintain residual system pressure." ("Bosh Fuel Injection"; Chapter 5 "Continuous Injection - Theory"; Section 3 "Fuel System"; Subsection 3 "System-Pressure Regulator"; para. 4)

Later, the manual points it out as a source again:
67409

A bad "3rd" o-ring could allow it to leak back to the tank via the 2 yellow paths in the following pic:
67407

[Bitsyncmaster]

Hehe, I thought we were on the same page the last time this came up. I'll try again :smile:

Yes, it seals rest pressure for what would be primary pressure when the engine is running. BUT, there is a metering hole/restrictor passage (see D:01:08, Fig 7) connecting the lower and upper chambers (primary and control pressure) in the FD......

More:
"The push valve controls the return of fuel from something called the control-pressure regulator. You'll see more about the control-pressure regulator in 5. Control Systems. For now, all you need to know is that the push valve 0-ring shuts off fuel return from the control-pressure regulator to better maintain residual system pressure." ("Bosh Fuel Injection"; Chapter 5 "Continuous Injection - Theory"; Section 3 "Fuel System"; Subsection 3 "System-Pressure Regulator"; para. 4)

Later, the manual points it out as a source again:
67409

It could leak as shown via the 2 yellow paths in the following pic:
67407

Is there an open hole at the end of unit? If not where does that vent to?

[Ron]

The same place as the Primary bleed off...The two yellow arrowheads are drawn in the FD return-to-tank port, pointing to the tank.

The last pic is drawn funny- there should be a carrier and plug on the right end...and it doesn't show the WUR output port in, I.E., port for the WUR's return-to tank line.

Look at WSM D:01:08 to see the 3 ports (Primary Pressure in, Return-to-tank out, WUR output in). I'd post it, but what I have is too low res to see anything useful.

See?

[Michael]

Me reading the last few posts on this thread. I don't mind admitting when I am lost:

https://media.istockphoto.com/photos/chimpanzee-playing-with-a-laptop-picture-id92236499?k=20&m=92236499&s=612x612&w=0&h=fKFgLUd_ApLEECRSJGOXzP0XZ_aRznVyHEPX3iUkaBM=

[Ron]

Found a better pic (but not much). Colors added.
67417

[Ron]

Here ya go, found what I was looking for:

"In order to fully seal off the control-pressure circuit with absolute certainty when the engine has been switched off, and at the same time to maintain the pressure in the fuel circuit, the return line of the warm-up regulator is fitted with a check valve. This (push-up) valve is attached to the primary-pressure regulator and is held open during operation by the pressure-regulator plunger. When the engine is switched off and the
plunger of the primary-pressure regulator returns to its zero position, the check
valve is closed by a spring (Figure 17)."

Note the Decoupling Restriction Bore (Fig 16; 4), where primary and control join.
67418
Note the 3 ports (Fig 17; 1, 2, 5*)
*This is from a 4 banger setup -- #5 will come in at 90° to the piston. instead of at the right end of the main bore.

[Bitsyncmaster]

OK. Now I see it with that last drawing. It was throwing me because the drawing was not representing what the PPR looks like. I knew the end of the PPR is a solid blocked fixture. It should have shown the #5 on the side of the drawing.

[Ron]

OK. Now I see it with that last drawing. It was throwing me because the drawing was not representing what the PPR looks like. I knew the end of the PPR is a solid blocked fixture. It should have shown the #5 on the side of the drawing.Same here!...until I had an issue I was pulling hair over. The control pressure was high (almost matching PP) and I found a clogged WUR screen. Correcting that helped, but the pressures still acted odd. Trying to figure out WTH, I ran across the last docs. Long story short, the passage between the FD's WUR return line port and the piston's bore had a short section of the smaller o-ring plugging it as well...
[As a side note: None of those drawings reveal that you can adjust the PP via the carrier crush washer thickness, somewhat... ;-]

[Michael]

https://media.giphy.com/media/xepQrrT6lxQTm/giphy.gif

[DMCMW Dave]

Not to nit pick, but wouldn't new seals be recommended once the banjo bolts have been loosened?

In a perfect world, yes. Recommended.

[Silverbullet]

Does anyone have the link to buy the parts handy? Also is there a pic or drawing to id the parts on the left side valve cover? A vacuum hose pulled off of the little round plastic thing that looks like a check valve, the line that goes to the Tee... I replaced it but it did not fix, is it related to the problem?

Craig