BlueByU

Here's my results:

injector
1. 14.8
3. 17.8
5. 17.9
7. 3.7

2. 8.2
4. 17.9
6. 17.8
8. 17.8

This was for a 1991 L98 motor. I'm thinking they all should be at about 17.8 ohm judging from the results. This means that injectors 1, 2 and 7 are bad and are not worth getting cleaned, correct?

I've heard of of people having problems with the LS1 injectors on TPI motors, so I'm thinking I will go with 24# svo's. The car is stock minus the catback. What do you think? Comments, suggestions, opinons are welcome

88 350 tpi formula

iTrader: (9)

I have always used svo injectors and many people I know not one has had a problem! pretty good I think. (like any product there will be some who have had problems)

I can't say as far as the other brands though

TraviZ

iTrader: (2)

#1 is fine, abit low, but wouldnt cause issues. #2 and #7 are just about dead. i replaced all mine with svo's and they work wonders and can handle the wrath of dry nitrous.

kretos

quick questiong how'd you test the injectors?

its something i've had no experience with and i'm kinda curious if mine are worth keeping or not

BlueByU

I took the connector off of the injector and touched the 2 little prongs sticking out of the injector with multimeter leads and wrote down the reading on the mulitmeter.

BlueByU

What does a low ohm reading on an injector do as far as affecting the operation of the injector?

All I know is a low reading is not good.

kretos

did it matter which leads to which?

DENN_SHAH

iTrader: (1)

low ohms cause high current flow through the injector drivers in the ECM which cause the drivers to over heat & burn out requiring either replacement of the ECM or repair of the ECM.
you need to replace injectors # 2 & 7 right away. i wouldn't spend any money on # 1 as it is starting to fail, i would replace it
with the others.
with the way resistance works, i forget the formula to figure just what the exact resistance is, but i would say your injector drivers are seeing somewhere around 1-2 ohms of resistance where hey should be much higher.
also, those low ohm injectors can can cause the other good injectors to not open as they should & cause the other cylinders to run lean.

Vader

Chances are that if the injectors are stock '91 parts, they are Multecs. If that's the case, they may not even be worth cleaning. The dead ones are certainly not.

Low resistance operating coils will require the ECM to switch more current than it was intended to. This may not only affect the life of the ECM, but may increase the voltage drop across the switching transistor in the ECM and result would be lower operating voltage for the remainder of the "good" injectors. This would tend to increase injector current even further, and create a cascade situation where the good injectors could fail sooner.

Moreover, the failing injectors may also not generate enough magnetic force via the failing coils to properly operate the pintle, and could result in fuel starvation in their respective cylinders.

The SVO (Bosch) injectors should work fine so long as you install the correct (GM dimension) 'O' rings when you perform the injector swap.

DENN_SHAH

iTrader: (1)

kretos, no, just good contact to the 2 terminals in the injector. also, while you are checking them, have 1 lead of your DVMM on either of the injector terminals & touch the other lead to the body of the injector, it should read an open curcuit, if it doesn't that injector is bad.

*edit*
Vader brings up a good point about them probably being multecs, if they are, they aren't worth spending much money on.

BlueByU

Is there a way to test if any of my ECM injector drivers have burnt out?

I'm ordering some svo 24#er's tonight.

DENN_SHAH

iTrader: (1)

if it was, your car wouldn't start or if it would start, it would run very badly.
normally when a driver fails, it won't turn on at all or it locks on.

rgarcia63

E is volts
I is current
R is resistance
E=I x R
E/R=I
Your lowest is 3.7 ohms at 12volts it drawing 3.8 amps.
Your highest is 17.9 is drawing 0.8 amps, your total current draw is 10.4 amps. the left bank is using 6.4amps, the right 4 amps.

The injector fuses on my 88 are rated at 10amps. My 30# Accel injectors resistances' are between 16.4 and 14.3, and draw a total of 3.75 amps per side at 14volts, that's about .875 to 1 amp per injector.

And, yes I know there's a large group that don't like Accel injectors.

Brazen

This subject should be "stickied" imho... if something similar already hasn't been (haven't searched yet)

On a side note, and not to hijack... can anyone identify these injectors for me? I've looked hi-n-lo on the net as well as asked several local mechanics and friends, with no luck. These were included in a car purchase but the guy I bought them from had no clue as to what they are... other than 47 lb injectors that were on the 91 Z28 when he bought it... which were WAY too big for the stock TPI intake system.
Thanx to ANYone who can help....
Jim

Brazen

Here's another shot
Jim

Mkos1980

iTrader: (8)

Thats what i was doing wrong. I was accually putting both leads on both prongs rather then one on its side when testing my injectors yesterday and they were ALL 16.1 no variation and these are stock 88 injectors. I knew it couldnt be that, that everyone was identical

91GTABird

I think i have found my problem.

Thanks Guys.

Im on my third 730' ecm and 3rd fuel pump with a lean condition. Going to ohm my injectors out tomarrow.

When you talk about ohming the injector from one contact lead to the body of the injector, are saying to not get continuity b/c if so then the coil is bad and touching the body?

Red Devil

I'd tell you guys to search for some of my threads on the TPI board for the part numbers etc. that will take the cir-clips et al.

Used to be able to search for 'morley' and my name and the big bruhaha post would come up that had links to two or three other threads that had the Ford Motorsport injector info in 'em.

Search is hit or miss now so if anyone can get it to work feel free to link it in this thread. IIRC I had part numbers for the blue tip 24# and the 19# (can't recall the color) looked up and listed.

I'll try again later if I can remember...

rgarcia63

Testing across the prongs gives you the injector coil's resistance, testing from the prongs to the body will indicate a short if there is any resistance. If one of the prongs were connected to the body which, makes contact with the intake (unless the injector body is isolated) which has a path to ground, would bypass the ECM, and the injector would be on as long as power is applied. The injector wouldn't last long at 100% on time.

BlueByU

I installed the new ford injectors today. The idle is so much smoother now! The motor revs so much smoother as well.

I used the o-rings that came on the ford injectors. I had also purchased a set of o-rings from napa for comparison to the ford's. To me it looked like the napa o-rings were ever so slightly fatter. However, the o-rings on the original multec injectors I pulled were fatter than napa and ford's. Perhaps partially due to swelling? I never did get any new GM o-rings for comparison. Also, the o-rings which came with the Felpro gasket kit I ordered were identical to napa's. I was going to use the napa o-rings, but the o-ring on the injector which goes into the manifold was next to impossilbe to get off due to the cap on the end of the nozzle. I'm not sure if those caps come off without breaking so I left them alone.

No leaks so far, but I'm going to keep a close eye on them for awhile.

Oh yeah, another reason why I didn't use the napa or felpro o-rings for the top of the injector was because they fit loosely around the injector, the ford's were really snug.

TraviZ

iTrader: (2)

good choice on the fords, 24lbsers i assume? i stuck with their o rings and everything is just dandy,

BlueByU

yes, 24lber's. That makes me feels better about the o-rings.

Red Devil

I used the Ford o-rings with no discernable problems (except for running a tad fat, but that wasn't really an o-ring problem, now is it? ). IIRC Vader actually has measurements comparing the two.

The 'banter' thread was 'kindly' pm'd to me. Ignore the drivel and just find the links if you need part numbers:
https://www.thirdgen.org/techbb2/sho...hreadid=271828


[Morley] You are mistaken, Accel produces nothing but immaculate and superior injector sets. If you hear anything other than that ignore it, it is a lie or misinformation from ignorant children. [/Morley]


Ok, ok, I couldn't resist, it's still funny.