Archived Installed stage II CP3, now problems!!!

[CStraface]

Just installed stage II CP3 from Floor It. Rail Pressure is going nuts. At idle it will be all over the place from 13 to 3. When I give it throttle it will be normal, but then when I let off the throttle and the RPMS fall to say 1000 the pressure spikes to 20 or 15 and stays there for a few seconds. When this happens there is a terrible ticking noise. Truck idles rough. Upon first start up, after installation, sounded like the truck was missing. I have since put the stock FCA back in, still having the problem. I have changed the rail pressure sensor.



Whats going on fellas? John at Floor-It says the problem is always fixed after that FCA is changed. Well not this time? Could this pump be amplifying another problem on the truck? Well if so, why wasn't the problem there with the stock CP3?



John overnited another pump. We'll see. Let me know though if anyone has experiance anything like this. Thanks.

 

[CStraface]

Cmon fellas? Anyone got anything for me? Someone has to have some idea... .

 

[Joseph Donnelly]

You might check the wiring harness connector very closely to be sure it is getting good contact with the sensors for rail pressure on the rail and the FCA on the pump. Your problem is unusual. John's pumps are very reliable and high quality.

 

[CStraface]

Yeah... thats why I went with his pump, but I'm pretty sure those connectors can only click into place one-way, and I have re-connected that FCA connection time and time again. I was thinking for some reason my ECM needs to be re-flashed, but why would it all of the sudden mess up once this pump went on the truck?



Lets throw on the pump that John hopefully overnited me Friday and hope the problem is fixed. If it's not... then I dunno.



Lets hope we don't have to go there.

 

[Joseph Donnelly]

If you are running a box or program that increases rail pressure, it could have gone bad. A box failure can result in maximum rail pressure at idle, giving poor idle stability with enormous clatter, as if you were running 50 degrees of timing. A poor electrical connection can give that result too.

I would not expect John's pump to be the cause; he uses good quality control and testing of his pumps. However, it CAN give more rail pressure than stock so could have exaggerated a problem that was already there. Or, reconnecting that one time could have fatigued and broken a wire, bent a connector out of place, or pulled a wire out of its connector.

 

[CStraface]

I have checked all electrical connections, they are all fine. I disconnected pressure gauge to see if that was the issue. It wasn't. I am not running a pressure box.



I bought the truck used, and have sometimes wondered about bad injectors, but so far so good, at least I think. Why would a new CP3 all the sudden cause irratic rail pressure? That doesn't seem to make much sense... . You tell me?



John just called and said he overnighted another pump. Should be here tomorrow. He put this one on a truck, rather then just the Bosch tester, and it tested fine. So hopefully once this thing goes on tomorrow problem solved.



If not, then I think I am going to pull the TST to see if that makes a difference, then if that does not fix the problem... . something is really wrong in there... .

 

[BradyWilliams]

Just the Bosch tester?

 

[CStraface]

Just the Bosch tester?

I will respond to that once I get the new pump... .

 

[HeberRam]

IMHO, I believe it is the cp3 pump. I would suspect that there is metal shavings in the pump due to the mod. If the replacement pump was properly tested by a qualified Bosch re-builder on a test stand I would say it will solve your problem. Let us know if the replacement pump works out for you.

 

[elandon1201]

IMHO, I believe it is the cp3 pump. I would suspect that there is metal shavings in the pump due to the mod. If the replacement pump was properly tested by a qualified Bosch re-builder on a test stand I would say it will solve your problem. Let us know if the replacement pump works out for you.

Pumps are EDM'd there are no metal shavings

 

[nwpadmax]

Don't know if this will be helpful or not, but on the Dmaxes, the twin pump kits are fairly sensitive to lift pump pressure. I had to get mine down under 12 psi or so and it smoothed right out. The 2nd-gen electronic control unit seems to have it under control, but I thought this is one variable you might want to look at.

 

[HeberRam]

Pumps are EDM'd there are no metal shavings

That's news to me, the last time I saw a Floor-it modded CP3 pump, they were still drill pressing the aluminum housings, gear pumps and fill valves. Even EDM ing the the fill valves can leave a bur which will cause the pump to not work properly. I don't know how they can be EDM ing the soft aluminum parts?

 

[Joseph Donnelly]

What is your lift pump pressure measured at the pump inlet?

John has refined his processes for modifying the CP3 and is over the hump on the learning curve.

 

[CStraface]

What is your lift pump pressure measured at the pump inlet?

John has refined his processes for modifying the CP3 and is over the hump on the learning curve.

I can't say I have checked. I do know though, that plenty of guys run Stage II's with the GDP lift pump kits. If there was a problem with pressure at the lift pump, wouldn't that have been reflected with the stock pump as well??? Just got the second pump from John, already have the ECM dropped, the lock key in the bell housing and the belt off the ps pump, so I got a few more bolts to pull off and I should have that new pump on.

 

[Joseph Donnelly]

Why drop the ecm? Just pull off the breather tube and rubber piece from the plate and nipple on the block.

While a stock CP3 is happy with any positive pressure and under 16 is fine, John's pump likes 45 psi. The FASS 200 will do it, with their 45 psi spring under the return fitting (inside the red pump block).

 

[CStraface]

Well does anyone know what the pressure would be with GDP's Walbro and the stock pump in line?

 

[CStraface]

Ahhhh, how sweet it is. The new pump is perfect! Trucks runs great again. I am sending the first pump back to John, so hopefully he can diagnose what the issue was.

Just the Bosch tester?

I guess sometimes the Bosch tester doesn't pick up everything.

 

[TheWolf]

Well does anyone know what the pressure would be with GDP's Walbro and the stock pump in line?

The walbro kit has shims that you use to adjust your pressure to where you want it.