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Need schematic or diagram of Injection system 94 STS


The Fred

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Can anyone scan that part of the service manual for me?

Or briefly explain it to me?

There are two 10A fuses and when I remove one with the car running nothing happens.

MerryChristmas

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No one has chimed in, so I'll give you 1997 model year information. I suspect that electrical data about the fuel injection will apply to the 1994 model year.

There are two 10 amp fuses for the fuel injectors (page 6-265). They are:

[Hot in Run, Bulb Test and Start]

Power Distribution Cell 10 on hot side of fuse.

Fuse label is INJ, position is B9, and wire is PNK, goes directly to injectors for cylinders 2, 3, 5 and 8.

[Hot in Run, Bulb Test and Start]

Power Distribution Cell 10 on hot side of fuse.

Fuse label is INJ, position is B7, and wire is PNK, goes directly to injectors for cylinders 1, 4, 6 and 7.

The injectors are grounded through the PCM. Injectors for cylinders 2, 3, 5, 8, 1, 4, 6 and 7 are connected to PCM terminals 10, 12, 17, 22, 9, 13, 18 and 11, respectively.

Fred, if pulling one of these fuses doesn't do anything, you have four dead injectors. The first thing I would do is check the fuse, then the connectors and wiring. With four cylinders, you have 50 hp.

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No one has chimed in, so I'll give you 1997 model year information. I suspect that electrical data about the fuel injection will apply to the 1994 model year.

There are two 10 amp fuses for the fuel injectors (page 6-265). They are:

[Hot in Run, Bulb Test and Start]

Power Distribution Cell 10 on hot side of fuse.

Fuse label is INJ, position is B9, and wire is PNK, goes directly to injectors for cylinders 2, 3, 5 and 8.

[Hot in Run, Bulb Test and Start]

Power Distribution Cell 10 on hot side of fuse.

Fuse label is INJ, position is B7, and wire is PNK, goes directly to injectors for cylinders 1, 4, 6 and 7.

The injectors are grounded through the PCM. Injectors for cylinders 2, 3, 5, 8, 1, 4, 6 and 7 are connected to PCM terminals 10, 12, 17, 22, 9, 13, 18 and 11, respectively.

Fred, if pulling one of these fuses doesn't do anything, you have four dead injectors. The first thing I would do is check the fuse, then the connectors and wiring. With four cylinders, you have 50 hp.

50HP!!!

That is what I have!!!!!!

I checked the fuse all out too

I can't tell where the wires go.. can you tell me where the PCM is?

MerryChristmas

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I took off the cover so I can see the wires but I can't seem to trace them back to anything yet

I took off the cover so I can see the wires but I can't seem to trace them back to anything yet

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Did you check for a bad fuse? By swapping them you didnt prove anything the good fuse would just run the other bank of injectors... Do you have an ohm meter or continuity tester to test the fuse? What type of fuse is it a MAXI fuse?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

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Did you check for a bad fuse? By swapping them you didnt prove anything the good fuse would just run the other bank of injectors... Do you have an ohm meter or continuity tester to test the fuse? What type of fuse is it a MAXI fuse?

I did prove that both fuses are good, I think, because the fuse that I removed that didn't do anything, I put that into the other injector fuse spot and the motor runs fine...

It's just a small blade style fuse is what it is

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If you have a meter or a tester with a bulb, you can verify that you have power to the output of the fuse. From there, power goes to the injectors, and that's the wire I would check. After a junction, you are looking at wires to each injector and then to the PCM, not four at a time.

To answer your question, though, the PCM is under the air cleaner element. It's the box with the cooling fins.

FWIW, I based the 50 hp figure on a Car and Driver test. When the limp-home mode was introduced, Car and Driver drained the water out of a test car (an STS, I believe) and tested it. They determined that the engine ran on four cylinders moved around at random to prevent any given combustion chamber from getting too hot, and they ran 0-60 mph and quarter-mile times on it. Based on those times, they estimated 50 hp.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
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Fred if the car is running on 4 cylinders I think it must be running HORRIBLE.. I don't believe that fact has been fully detailed. Is this car running horrible?

You took it to Wichita how far is that?

Your quote > "Well it did alright on the way to Wichita.. still the same rough"

I guess because they have the Fuses controlling cylinders that will permit the engine to run on 4 cylinders, that was the roughness you were feeling. I would imagine that it would feel like a vacuum leak or ignition related problem... I don't think we have ever run across this problem before. This was a good catch Fred to notice the fuse issue and Jim this was a good find and read from the manual... This has been a very interesting thread..

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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If you have a meter or a tester with a bulb, you can verify that you have power to the output of the fuse. From there, power goes to the injectors, and that's the wire I would check. After a junction, you are looking at wires to each injector and then to the PCM, not four at a time.

To answer your question, though, the PCM is under the air cleaner element. It's the box with the cooling fins.

FWIW, I based the 50 hp figure on a Car and Driver test. When the limp-home mode was introduced, Car and Driver drained the water out of a test car (an STS, I believe) and tested it. They determined that the engine ran on four cylinders moved around at random to prevent any given combustion chamber from getting too hot, and they ran 0-60 mph and quarter-mile times on it. Based on those times, they estimated 50 hp.

That is odd you'd mention limp home mode.. the whole time this has been going on I have been saying to myself, this thing is acting like it is in that limp home mode I've heard about.

Fred if the car is running on 4 cylinders I think it must be running HORRIBLE.. I don't believe that fact has been fully detailed. Is this car running horrible?

You took it to Wichita how far is that?

Well it did alright on the way to Wichita.. still the same rough

I guess because they have the Fuses controlling cylinders that will permit the engine to run on 4 cylinders, that was the roughness you were feeling. I would imagine that it would feel like a vacuum leak or ignition related problem... I don't think we have ever run across this problem before. This was a good catch Fred to notice the fuse issue and Jim this was a good find and read from the manual... This has been a very interesting thread..

It is running horrible, yes sir.. Wichita is only 40 miles from here.. . I have to drive the car like an old truck the big huge lack of power has me shifting it with my foot because otherwise it gets confused and shifts too darn hard at around 4000. And it doesn't want to go over 73- I think I could force it to but it acted like it would be really very rough on it so I didn't try too hard.

I can't believe I didn't notice the fuse sooner I guess we all assumed that if a fuse was out it would just shut the whole thing down, didn't we :)

I've now had one and a half fresh tanks through the car (I ran the first fresh tank down to almost nothing for obvious reasons before refilling it)

MerryChristmas

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You drove a car running on 4 cylinders up to 73? OMG! :lol:

Quote > I can't believe I didn't notice the fuse sooner I guess we all assumed that if a fuse was out it would just shut the whole thing down, didn't we.

I don't think so I dont think we ever ran across this before in my time here (about 7 or 8 years)

I just think this was bad communication as it started out with bad gas, water in gas, O2 codes, FPR leaking and this statement you made:

First problem happened when I got gas at the KWIK shop.. was low on gas put about 1/4 tank in. Awhile later it was running just a little bit rough I'd say it was running about 90% normal. No bogging down at all. Then I had a no start condition until I added some gas from Conoco and after I mixed that in it cranked a little while and started up and was just perfect.

A couple of weeks later I got gas at the KWIK shop again. was very very low on gas and put about 1/2 of a tank in there. Drove up to the parking strip, went in to pay, came out and started it up - as soon as I was driving off it started acting up and bogging down quite a bit.

These to me are not statements that would logically lead one to 4 cylinders NOT firing.. It leads you to the direction we headed, bad gas, water in gas, O2 codes, FPR leaking.....

This was probably the most frustrating thread in my entire tenure here.

Fred this is something that you SHOULD have stressed MUCH earlier in this assortment of threads:

Your QUOTE >> I have to drive the car like an old truck the big huge lack of power has me shifting it with my foot because otherwise it gets confused and shifts too darn hard at around 4000. And it doesn't want to go over 73- I think I could force it to but it acted like it would be really very rough on it so I didn't try too hard.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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You drove a car running on 4 cylinders up to 73? OMG! :lol:

Quote > I can't believe I didn't notice the fuse sooner I guess we all assumed that if a fuse was out it would just shut the whole thing down, didn't we.

I don't think so I dont think we ever ran across this before in my time here (about 7 or 8 years)

I just think this was bad communication as it started out with bad gas, water in gas, O2 codes, FPR leaking and this statement you made:

First problem happened when I got gas at the KWIK shop.. was low on gas put about 1/4 tank in. Awhile later it was running just a little bit rough I'd say it was running about 90% normal. No bogging down at all. Then I had a no start condition until I added some gas from Conoco and after I mixed that in it cranked a little while and started up and was just perfect.

A couple of weeks later I got gas at the KWIK shop again. was very very low on gas and put about 1/2 of a tank in there. Drove up to the parking strip, went in to pay, came out and started it up - as soon as I was driving off it started acting up and bogging down quite a bit.

These to me are not statements that would logically lead one to 4 cylinders NOT firing.. It leads you to the direction we headed, bad gas, water in gas, O2 codes, FPR leaking.....

This was probably the most frustrating thread in my entire tenure here.

Fred this is something that you SHOULD have stressed MUCH earlier in this assortment of threads:

Your QUOTE >> I have to drive the car like an old truck the big huge lack of power has me shifting it with my foot because otherwise it gets confused and shifts too darn hard at around 4000. And it doesn't want to go over 73- I think I could force it to but it acted like it would be really very rough on it so I didn't try too hard.

Sorry about that..

The last 70 days have been the most taxing days of my whole life and my mind has been everywhere - you wouldn't believe how many things I've had thrown at me all at once.

It may be no excuse but I feel that I should explain myself :)

MerryChristmas

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If you have a meter or a tester with a bulb, you can verify that you have power to the output of the fuse. From there, power goes to the injectors, and that's the wire I would check. After a junction, you are looking at wires to each injector and then to the PCM, not four at a time.

I will check that... I have a hard time believing that there is an issue with the injectors themselves since it seems like one fuse must be for 4 and the other for the other 4 and that most mean that one bank just isn't getting power or some thing like that

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I tried to check the power at the fuses but it wouldn't show a reading on any of them.. am I supposed to ground the black wire some where and test that way?

Now, when I pull that fuse that didn't do anything.. there is a very very very slight change in the idle so maybe you are right about looking for problems with individual injectors..

I don't know what on earth caused this and it sure is funny that it started right after I got gasoline

Darn I can't remember where the wires coming from the injectors go.. I sure would hate to have to borrow the torque wrench again.

I got under there and cleaned the connectors real well

MerryChristmas

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I thought it was going to the dealer today for a diagnosis...no?

I cancelled that but I had to make a new appt. since I still can't figure out what ails the car ;)

MerryChristmas

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http://caddyinfo.ipbhost.com/index.php?showtopic=5803

SOME OWNERS MAY EXPERIENCE AN INTERMITTENT MISS, SURGE OR LACK OF POWER ON A MODERATE TO HARD ACCELERATION OR AT STEADY SPEEDS WITH NO PCM DTC CODES SET.

CAUSE:

THIS CONDITION MAY BE CAUSED BY AN INTERMITTENT SHORT TO GROUND ON THE PARK/NEUTRAL INPUT (PI79) TO THE PCM. THE PARK/NEUTRAL INPUT (PI79), IS A NORMALLY "HI" INPUT TO THE PCM WHEN THE GEAR SELECTOR IS IN ANY OF THE DRIVE POSITIONS AND "LO" IN PARK OR NEUTRAL. IF (PI79) GOES "LO" WHILE DRIVING, THE PCM WILL ENABLE THE TORQUE MANAGEMENT MODE. DURING THE TORQUE MANAGEMENT MODE, THE PCM WILL REDUCE ENGINE POWER BY RETARDING THE TIMING AND SHUTTING OFF 4 INJECTORS. THE PARK/NEUTRAL INPUT, CIRCUIT 434 (AN ORANGE/BLACK WIRE), MAY BE SHORTING TO THE TRANSAXLE CASE NEAR THE PRNDL SWITCH CONNECTOR (SEE FIGURE 1).

CORRECTION:

TO REPAIR THIS CONDITION, USE THE WIRING REPAIR PROCEDURES IN THE SERVICE MANUAL, SECTION 8A-5. AFTER THE CIRCUIT HAS BEEN REPAIRED, THE HARNESS SHOULD BE REPOSITIONED USING PLASTIC TIE STRAPS TO PREVENT CONTACT WITH THE TRANSAXLE CASE CAUSED BY ENGINE MOVEMENT DURING ACCELERATION.

Would love a darned scan of SECTION 8A-5

MerryChristmas

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Well I took the cover off and it looks like:

Two of the injector gaskets (green color) are broken... hmmm

Also a couple of them look clogged

Can't drive it right now the parts store doesn't have the gaskets and so in the morning instead of driving in for diag I will go there and buy the gaskets.. also I found out where I can get the bottle you run the motor off of to clean the injectors(amazing)

And since I don't want to know,

How much do injectors cost for this beast?

MerryChristmas

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Are they gaskets or o-rings?

I tried to clean the injectors on a 3100 Pontiac and clogged them. I bought two injectors from the junk yard for about $20 each..

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I forgot, don't attempt to physically clean them, you will clog them

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Can anyone scan that part of the service manual for me?

Or briefly explain it to me?

There are two 10A fuses and when I remove one with the car running nothing happens.

Fred,

If you're still interested in the FI schematic I can email it to you. I can't post it due to file size restriction. I tried a number of scan settings but could not produce a legible image within the acceptable file size range.

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Most e-mail packages will work OK to about 10 MB attachment sizes. That's too large even for a full-page scan of line art and text; parhaps you should keep trying to get the file size down. Try scanning with black/white bitmap (not grayscale) to a TIFF file with Zip compression. Or, do a little more experimentation with scan image types and output file types.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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:angry: One of my cover bolts is stripped :angry:

I think I can fix it because it is on the end and I can get a nut and bolt through it...

Prayer prayer prayer say a prayer :unsure:

MerryChristmas

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I always have good luck with Jpegs at around 50%

My e-mail is fredmaxwell@cox.net

Thanks

PS: I can't get anyone to believe me that these green things came off the injectors *sigh*

Idiot tried to tell me I had taken it off of a spark plug or pcv valve

I don't look that stupid, my lord.

Going in, in another 40 minutes for diag

Prayer and more prayer

MerryChristmas

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