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DS4 IP experts

Twisted Steel Performance

Twisted Steel Performance

Anything worth doing is worth overdoing.
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Pauline, SC
I have a new build on the run stand and I'm having a lot of trouble getting the timing set. Everything I'm using was used a month ago so I know that part works, and I use GMTD on my laptop and have done it before.

Now, this time I'm using the customers used IP & injectors, and pmd extension harness, my known good pmd. It's very hard to start, very smokey burn yo eyes fuel, doesn't want to idle, skips and smokes worse if reved up...

Once hot, click time set, it won't idle if I try and get lower than 7*, target is 3.5* ......... get it to 4.5* and click offset learn it dies instantly, doesn't want to restart...

No matter how much I move the IP, I can't get the offset to change from -2.02 .... and it always throws the offset error code....

I'm so new to the ds4 y'all lead me where to go from here, I suspect IP or maybe a sensor but not sure how to diagnose .....
 
Those OBD1 systems can be a bugger to get out of that -2.02 mode. If you set the IP so the top of it is level it should be in the ball park. Then start it and immediately try to do time set. No waiting at all. Might have to do the resistor mod to fool the ECM that it's up to temp.
 
I have always had good luck when I set the base timing to 3*. it could be a finicky PCM too. being a new build with tight tolerances there is really finite movements of the IP to get it there.

if you have another truck or setup where you don't have to swap IP's out and just plug in that PCM and attempt to do the time set procedure, that would get the PCM out of that loop. would also rule out if the PCM is the issue.

when I was leaning and did this for the first time on my 95 and me not knowing any better, I actually did the first time set loosening the IP nuts and snugging the top one, adjusted the base timing with the engine running watching the laptop. a last ditch effort that might help.

before the build, I assume this IP was on your customers engine and running fine. if it had an engine failure that may have caused damage to the IP or maybe damage during shipment. IDK how fragile DS4's are if a package was dropped and kicked around during shipping.
 
This IP was on a motor that failed, the owner says he thinks it was working when it was removed.

The prom I'm using is a prom quadstar sent me to use for this testing on my stand. I do have the owners prom I'll swap and try to see if that makes a difference.

I could swap a db2 in to prove the motor, but that is a lot of work and doesn't show the owner the motor is right with his IP, so I'll keep working to see if I can get this figured out. I'm sure it's not the PCM as the motor I ran a month ago was perfect with a new IP so it's something with this pump I think... I'll wait till the owner gets back in town to see what he wants to do..
 
Doing some searching I think I should check the optic sensor and steeper motor to see if they are working..

I'm not a electronic pump person till now, so could someone tell me how to check and maybe replace these items, and every time it throws a relearn error code, I have cleared codes, unplugged the ecm, nothing clears the code so that might mean the steeper motor is stuck but how to test...
 
Testing the optic is simple. unplug the CPS and try to start it. it will take longer to crank but should start up and run. for testing the stepper motor, you can rotate the stepper arm on the side of the pump all the way one direction or the other and then key on. it should move iirc.

from my memory, the stepper essentially does the same thing as the arm on the side of a DB2 that pushes the plunger as you accelerate.

I was thinking about engine failure and wondering if it went full send overspeeding and maybe damaged the optic disk in the pump. you might pull the top of the IP and have a look inside. the optic sensor is attached to the top housing with a snap ring and has a single torx bolt that holds it to the rotor iirc when removing that bolt holding the sensor on the rotor, don't rotate stepper motor as that would cause misalignment. that's how they do an "optic bump" with the timing.
 
Thanks, everything has been disconnected over night, I'll head out and start from scratch and do some checks...

A few days ago I did disconnect the cps, when it did start it ran smoothly so I think that means that CPS is bad, I swapped another one and went back to running crappy...
 
do the opposite to test the CPS. unplug the optic sensor and try to start it. it should start and run but will take a little more crank time. should run smoothly as well.

having one or the other disconnected will put the engine in limp mode and set a code for what's discoed.
 
I'm being told OBD2 can't be done like this, all I'm doing is getting the pump in place so the owner doesn't have to move it, he knows he will need to time it to his pcm... My setup let's things talk enough then I unplug, as long as the pump is right it's a breeze for him and it proves the motor runs...
 
I have all the usual plugged in so they are seen. I use water temp, CPS, all the IP plugs, and lastly the harness has the OBD1 plug and requires a OBD1 ECM...
 
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