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b95 VP 50efi idle problems

duken

New member
Freshly (dealer) rebui

Freshly (dealer) rebuilt VP 5.0(Ford)fi. It hunts up and down from 700-1050 or so and can't find a steady low idle. VP rep says its normal in this older model of computer after rebuild. Said 10-15 hrs of use and it will find equilibrium..is this true? Hasn't yet. All else works like a charm. Thoughts?
 
"Check for codes, specifically

"Check for codes, specifically MAP and TPS input. Also, do a compression check if you haven't yet."
 
Look for a PCV valve and make

Look for a PCV valve and make sure it's not sticky and that the hose is seated properly and there aren't any cracks in the hose.
 
I'll dig into it this week

I'll dig into it this weekend and check those things. Any idea about the computer and the comments from the Volvo rep? He said something about it being a first generation self calibrating system. If he's full of it I would like to rule that out.
 
"Look for the ECM- if it shows

"Look for the ECM- if it shows Delphi on it and is about 1-1/2" x 4" x 6" with a large connector on each end, it's probably a MEFI 1 controller and AFAIK, this wasn't actually self-calibrating and was a very simple program. Was the rep in the service department or sales? I would call and ask for technical help and you may get a different answer. I worked on MasterCraft boats and Mercruiser when I was in the business and both originally used the Delphi controller. In '98, when I was at the Regal dealer meeting, I talked to the VP of service for V-P and at that time, they were still using Delphi, so I think the systems were pretty similar between MC and V-P, although Merc had changed to a Motorola controller.

Look at the front corner of the throttle body near the throttle plate for a four-wire harness that has a pair of blue wires and a pair of green wires. This is the IAC (Idle Air Controller) and controls the idle speed, via input from the ECM. Each wire has a white or black tracer on it but unless they were yanked out or damaged, it's not going to change and for this, their positions don't matter (if they're in the wrong position, the IAC won't work properly).

Why was the motor rebuilt? Has any electrical work been done on the motor?

The things I would check now are:

All ground connections for the ECM, main harness, knock sensor module, distributor, relays, block and the battery posts/cable clamps. If you have the GM distributor with two harnesses on one side, make sure the IC module boats aren't corroded and are snug. If the cap and rotor are old, replace them- same for the plug and coil wires. Look on the coil for cracks and carbon traces. Old plugs? Get new ones. Check the base timing- this can't be done without putting the ECM in diagnostic mode. Some scan tools have a button for this. If not, you can use a paper clip- let me know if you do or don't have a scan tool with this feature. The idle needs to be at 1000RPM to set the base timing to 10º BTDC. Any time a motor is rebuilt, this needs to be set and just putting the distributor in, getting it to start and calling it good is not going to work."
 
"I bought the boat from a deal

"I bought the boat from a dealer and it looked and ran cherry when I bought it, considering it's 12 years old. Ran it in the local lake and the first time I had it out it started fine then smoked and sputtered. Turns out a detonation blew a hole in the top of the piston. Dealer felt bad and had motor rebuild for nothing!

They did what seemed like a great job except for this idle problem. They scavenged everything off of the old mill. I had it back for some crossed wire probs with bilge, blower and some guages that were disconnected. They took care of everything when it was winterized this past fall.

Funny thing is, sometimes it idles fine for 5-10 minutes at a time. Then it starts hunting. It does it with and without a load on it. Then it will smooth out for a while, then go back to hunting.

I'll have to dig into the basics this weekend with the vacuums, grounds and standard stuff. I don't have a code reader though, which would be nice. I'm not certain, without looking, but I believe I've have a delphi controler.

Can this efi setup base timing be checked with a timing light and distributor adjusted like an old points set up? Or must I have the reader? I'm sure I can't just run down to the local Pep Boys and pick one up.

Is there any way to upgrade the delphi controller without redoing the whole harness and sensors? Or am I locked into what I have without spending a boat load (no pun intended) of money?"
 
"I repeat, look for a vacuum l

"I repeat, look for a vacuum leak--especially since it was dealer rebuilt.

Jeff"
 
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