bureau13

I'm pretty convinced at this point that some of my on again/off again roughness is at least in significant part an injector issue. While I don't know this for sure, I figure a good ultrasonic cleaning by Witchhunter isn't going to hurt anything...it was that or just get replacements, and I think I'm going to try to stick to my stock ones for now.

From what I've been reading, it's not that hard to get them out, you just have to use some force to get them out of the rails. The WSM doesn't seem to say anything about relieving pressure before taking off the rails...just catch any fuel in an "appropriate container." I guess it must not be so much then? Any other little tricks or hints I should be aware of?

While perusing the WSM I did notice that there's a connection that differs between Cali cars and the rest of the US (on the throttle body, I think). I know it has nothing to do with the rails, but...my car is a Cali car, but it's not in that state any more...should I change the connection there? Does it matter?

kombatrok

Pull the fuel pump fuse while running. Let the car stall and that will relieve a lot of the pressure.

SMTCapeCod

Not much comes out, you can alleviate residual via the fitting on the front of one of the rails. Caution though IIRC there is a ball bearing for sealing in there.

You're right, cleaning existing is likely easier than sourcing new, given the variety available.

Use caution though, several folks have found the wires fatigued from being worked or being at sharp bends for so many years--- don't use too much (misplaced) force pulling the connectors off!

hwyengr

Agreed. Don't use any force at all. Get the spring wire clips off entirely so that the connectors just come apart with ease. Don't just loosen them and pull. The underhood plastic has zero give to it anymore and will snap with surprisingly little resistance.

16vsilverstreak

I second all the above. I recently did an '88 S4 intake refresh, hard and brittle plastics, the knock sensor insulation was severely cracked and falling off the cable.

bureau13

Good info, thanks. I have already noted that the boots on some of the connectors are splitting, although the wire itself doesn't look too terrible. Yet.

Tom111

If you need injectors PM me I have a set of used 8 balance & blue printed puppies ..... I purchased them yeeeeeears ago and have never used them.

(I'm talking circa y2k for my 88 I no longer have.... because they were from a rare factory built race engine and a rennlister ).

Tom

bureau13

Tom,

If they were for an '88 wouldn't those be the 19 lb/hr S4 injectors? Or were they upgraded for mods, given the race engine origins?

I'm going to send mine out and see what happens, but if some of them can't be brought back into shape, I may well be in the market. What happens if, say 6 or 7 of the 8 are good? Given that they're supposed to be matched, how do you round out the set, or do you just get a new set of 8?

Jfrahm

Did you localize this problem to a particular jug?

I have a couple sets of 4-hole EV6 24 pound injectors that might work.

bureau13

I have not. The issues are somewhat intermittent, but driveability, which had been getting worse, improved quite a bit after I ran some Liqui-Moly injector cleaner through it....but it's still not solved. However the improvement I did see was a pretty clear indication that the injectors were likely the problem, and at any rate, they're almost 30 years old....so a good cleaning or replacement can't hurt. I decided to try the cleaning first, and stay with the stockers, so I know they match what the Porken chips were programmed for, even though I know others have used 4-hole injectors and not reported problems. Also, cleaning at Witchhunter is usually cheaper than buying new ones, as a bonus.

davek9

Witch Hunters site has test and cleaning tips, the Bosch Injectors typical have an impedance right around 16 Ohms (in testing some recently I found 15.8 to 16 ohms) all within spec.
If say one was > 16.5 or less then 15.5 I would think it would need to be replaced.

Then there is the pressure test pump them up using a miti-vac to 19 - 24 psi whichever applies and see if they hold, then use a 9v battery it re-leave the pressure by momentary clicking them off.

Witch Hunter recommends not to use 12v as it can over heat the coils w/o fuel flowing.

IIRC they run ~ $20. / injector to test and clean plus shipping and I would send at least two extra just in case one or more is bad (there is an extra charge for each extra you send) .

IMO these are wear items and given the age and duty cycle, I went w/ new 4 hole Bosch on the Gold 86.5, however I did clean and test the ones in my '85 with good results too, next time I'm in there I will go w/ new too.

Dave

bureau13

I will definitely test the coils on these before I send them out. It certainly makes no sense to pay to clean them if the coils are not up to snuff. Good idea...

I keep going back and forth on cleaning vs new (even "new" are not really new I think...Roger's are refurbed 4-hole injectors, I believe). There was some disagreement on a previous thread about injector latency causing performance to vary which at least hypothetically, could be an issue when using programming that was intended for a very specific injector profile. I don't know all that much about it, but it made sense to try to stick with stock given that. I could be completely wrong of course...

Jfrahm

Running better for a time after adding injector cleaner is exactly what I've seen when I got some bad gas, and it took a lot of driving and several tanks to flush it all out. Both times I was on a long trip and could not easily drain the tank. I guess I do not see a connection between intermittent poor running and injectors needing cleaning. I would not invest in cleaning the old-timey injectors myself, I like the 4 hole EV6 injectors a lot so far. I got some 24s to try in my supercharged car (and a couple sets for the 968s).

-Joel.

bureau13

I guess it's not necessarily clear that cleaning them will fix them, but for relatively low money, it can't hurt. Honestly, the best reason to pay extra for "new" ones is that I can get them and swap them same day, without waiting a week or so to get the old ones back.

The thing is, a number of people were suggesting I had injector issues before I tried the injector cleaner elixir...so the issues are consistent with that. And it's definitely not bad gas, unless all I can get around here is bad gas, in which case I'll be living with it. The problems have been ongoing for a while now.