Gramps47

Just picked up my 85 today after having the master/slave cylinders replaced. While the car was there, I had the shop hookup the fuel system with this Motorvac CarbonClean system for about 60 minutes. Cost was $100 for the injector cleaning. I knew, IMMEDIATELY after starting the car, that this was a great investment. The car idled perfectly with no hesitation if given gas. I drove off right away and the car ran perfect. Even seemed a bit stronger, but I can't say for sure that it is. What I do know, is that it was a dramatic improvement in driveability. Just wanted to pass this along to the 944 nation. I've been around awhile, but this really got me excited.

mavfan

do most auto shops do this? is this safe on old injectors/fuel systems?

944S2NUT

I will be doing the same with my S2 in the next week or 2.

951and944S

Yep, MotorVac is awesome.
The guy I share the building I rent for my tranny shop has the system.

A week or two ago I was suspecting a leaky injector on my son's 87S so we hooked up the MotorVac to it but the pressure rating was not right on the supply of the cleaning chemical from the machine and the car died after only running on it for 10 seconds or so.

We ended up having to reattach the car's fuel supply to get it fired and decided to try again another day since it was after closing time.

Even with just this small dose of cleaner run through his fuel system, the car starts almost before you can get your hand off the key and the dragging of tickover (thought a cylinder was filling from leaky injector) is pretty much gone.

As an aside- I just removed the intake manifold from a Rennlister's car (ELLSSUU) about a week ago.
Car has around 90,000 on the engine and his intake tracts of the cylinder head and intake valves look like they just came out of the glass bead blaster they're so clean.
I've never seen even an engine even with half the mileage this clean.
He uses Chevron fuel with Techron.
I just switched.....;o)

TS

Peckster

With only 4 posts this guy is probably a schill. The stuff is not as good as a real injector cleaning but might be better than nothing in they are in really bad shape.

951and944S

Peck, I know you don't regularly get replies to your post so-

The MotorVac cleans, injectors, intact tracts, intake valve deposits and carbon from tops of pistons.

How is this "not as good as a real injector cleaning" when getting injectors properly serviced not only JUST addresses the injector itself but requires removal (labor) of the injectors themselves....?

The cleaning agent cost around $25 a pint iirc, $100 with labor is a bargain....

TS

bearone

or 3-4 tanks of chevron sul does the same thing.

87951

FRporscheman

I cleaned my injectors by removing them and using an air compressor, 12v source, and carb cleaner. The car now starts after only 1/2 crank, idles perfect, and everything else you said. One can of carb cleaner cost me about $4, and the 12v source was just my car battery charger. I think the 2 hours of labor was worth saving $100, but that's because I have low income and I'm handy. This motorvac may be a more viable option for the less mechanically inclined, but I myself prefer the old fashioned cheap way.

As far as results, I like cleaning each one individually to observe the flow characteristic of each injector, so I know exactly when each one is done, or if one is broken or something. If you run the motorvac and you get good results, then that's great, but how do you know all 4 have been equally and completely cleaned? Just IMHO.