wiredright3

Hello Rennlisters

1st off I have to confess the 928's (all 3) are not mine. I am working on them for a friend/customer (more friend). I am an International Harvester fan myself, own a 1968 and a 1966 Scout 800

Anyway. I got this small problem and could use some help. I searched already, and the amount off issues and possible fixes for this are numerous. I'm trying to get this car right and delivered today.

It's a 1987 928 with a 5spd. It has a 302 motor in it. Problem with the 3 928's he has is that each one has a different motor in it. (Plenum looks different on each) so it's hard to "get familiar" with it.

I was asked to put on and finished:

Plugs (Bosch Platinum Plus, #4601)
distributor Caps and Rotors
Wires (Magnecor Competiotion series)
Thermostat
New (used) Power Steering Pump
New belts
Flush Radiator
Pads and Rotors all the Way around

Porsche Ran Fine before I finished

So I finish up, fire her up. runs good. No issues, drive up to store and back to get brakes set. No issues. Runs about 15 minutes and 2 miles.

Get back to the shop and stop. It's sitting there idling fine, then suddenly it starts to lope/surge. I get idle of about 700-800 RPM, then it drops to almost 200 seems to almost stall, then jumps back to 700-800 ands holds it for a second or two, then repeats the process. It hasn't stalled, but I wouldn't let it run much when it started that.

I checked every connection and vacuum hose , can't find anything loose or broken/disconnected.

I cut the smog belt per his request. The muffler/pipes have been redone, and the cat removed (I assume 02 sensor too??) this shark has electric fans, so no bypass belt like the last one I worked on.

Last point of interest, the plugs I removed were fairly new. They were however the Bosch +4 platinums. They were also a little sooty. Only Time I have ever seen anyone use the +4's were mostly novices trying to adjust for a rich or oil fouling issue by "increasing spark" .


Thats all I can think of for info. I have tried pulling the neg cable from battery trick...no go

Did I do something to it? I had zero issues with the other two and naturally this is the most expensive and nicest


Help?

wiredright3

BTW

Here she is

Mrmerlin

I would do a dark run test and look at the ignition wires as a suspect. FWIW Roger@928sRus.com has the correct Beru wires that are plug and play for 300.00 .
Since the ignition system is the last thing you worked on it stands to reason that you have a bad part or crossed wires or a bad ignition coil wire there are 2.
The dark run test will usually show you where the spark is leaking

SeanR

Might also have knocked a vac line loose. *edit, you already checked that. opps.

Don't waste your time and money on the plat plugs, go back to the copper ones. Also, if you knocked the bowden cable (throttle cable from the body to the assembly on the drivers side) the throttle position sensor (TPS) might not be making contact for the idle maps.

wiredright3

Well I put the old plugs back just for kicks

She runs great

or so I thought.

ran her about 5-10 miles and no problems


back home, and shes surging again. I get 700 - 200 hunting quickly but doesn't stall

I am lost now

wiredright3

Hmm., after a few beers and watching her idle. here is a new clue

When the fans kick on she starts to hunt for idle

Fans kick off and she purrs like a kitten

runs like a scalded dog otherwise. can't be mismatched plugs/wires etc...vacuum hoses and connectors all tight

No warning lights or anything
Alt needle doesn't drop

Fans off she seems to calm down

this is most peculiar. These are my first 928's, but not my first time around the block

Mrmerlin

check the battery ground at the rear of the car and then check to see what kind of charge is being provided by the alternator.
Open the 14 pin connector above the hot post and inspect for shedding insulation or corrosion.
Remove all of the fuses and clean them with an eraser.
Inspect the relay pins for corroded pins and corroded pins the relay should be opened
got 928gt.com for a fure/relay chart on page 2 under tips and links

georgeb

I had a simular problem the difference was when I tuned off my headlights the idle problem was ok, headlights on and the idle surged up and down to the point of almost stalling. Through trial and error. it was the mass flow sensor that caused the poblem

wiredright3

Thanks for the suggestions

My friend decided to pick it up and drive it. I haven't heard anything yet. I suspect MAF as well. I sprayed the screen with MAF cleaner, but otherwise didn't remove or mess with it.

I guess I will find out.

One question, cutting the smog pump belt wouldn't cause idle issues would it. Especially with no cat exhaust already installed?

What is a "dark run test?" All I can think is maybe something to do with Jedi's and medichloreans??

thanks

AO

Dark run test = run the car at night in the dark. Open hood look for sparks. A mister with water can help illuminate the issue.

wiredright3

Oh! I know what that is lol

just never heard it called that

wiredright3

Well, he came and picked up the car. Ran funny at first, called 2 days later says its fine (??)

Meanwhile, I looked and couldn't find a classified section here on Renlist.

I have a full set of Pads and Rotors for a 928 in great (almost new) condition.

He put all new crossed drilled etc on the shark, and I have this pile here. Brake pads are over 95 %. I think the brakes were done shortly before my friend bought it.

I couldn't throw them away, they are expensive for you guys.

Also have 2 spare drive belts in good shape and the old power steering pump (I understand they can be rebuilt) I will throw these in the box

I am a scout nut, so I feel your pain about losing stuff to the scrapyards. If I posted in the wrong section my apologies...I clicked on classified but it took me to another site I couldn't figure out.

Shipping zipcode is 27587.

Best offer...you know what they are worth not me, and I'm not looking to get rich at all :-)

Dave

wiredright3

I figured someone might want for a spare shark they are not ready to spend the big bucks on.

I forgot to mention just in case. This is 4 rotors and all the pads. front/Rear

bernard farquart

Classifieds are open to those with membership, "for sale" posts are looked upon poorly by those without membership. This is all covered in the admin post at the top of the forum.

wiredright3

Oh, sorry

I can't afford to be a member. They are not even my 928's, he's a friend. He said he didn't want this stuff back. I just thought someone would want. I saw for sale ads (for complete sharks) while I was searching info.


shame though....we in the scout world do not charge in order to "help save the breed". the classifieds are free if you just register..

No offense meant, but I don't agree with that. I have been an IH enthusiast for years, and we would rather just save the parts.

Anyway, I guess I will toss them. No one locally seems to want.

Please again, no mean to offend..just cause I don't agree with the membership thing

Thanks for the help in regards to earlier part of post. they are nice cars, just an enthusiast for a different breed here :-)

Admin feel free to delete if you need. I am a stranger in a strange land here. I'm most certainly not trying to start anything


Dave