89 Bronco II new to me

[wyo58]

View attachment 31939

Temperature and Resistance Values of an IAT Sensor​

Consult your repair manual for the specific resistance values for your application.

Temperature	Resistance
100 C (212 F)	2.07 K-ohms
90 C (194 F)	2.8 K-ohms
80 C (176 F)	3.8 K-ohms
70 C (158 F)	5.4 K-ohms
60 C (140 F)	7.7 K-ohms
50 C (122 F)	11 K-ohms
40 C (104 F)	16 K-ohms
30 C (86 F)	24 K-ohms
30 C (86 F)	24 K-ohms
20 C (68 F)	37 K-ohms

 

[grumpy old man]

When I had the wire loom out I also checked the values of the sensors, all were in specified range with the exception of the O2 sensor which I could not find any spec or test procedure for, according to the 89 Ford emissions book I acquired. I even checked all the sensor values at the ECM plug when I plugged everything back in. That is what I find so frustrating, I have checked and rechecked everything I can think of and as yet I have not found anything outside of factory spec.

When I replaced all the parts I replaced the injectors because it had a couple of drippy ones, but all that work actually made it slightly worse. To say that I am stumped is somewhat of an understatement.

 

[Tiha]

You said the catalytic convertor was glowing?
that would mean there is unburnt fuel getting into the exhaust, or running rich.

have you ever done a compression check on this engine?

 

[grumpy old man]

Tell me about it. That is the whole issue. For an as yet undetermined reason this thing is dumping a lot of fuel into the intake. Did you look at the test results, that is rich beyond reason. You could probably run your lawnmower on what is coming out of the exhaust

 

[Tiha]

maybe pull the spark plugs and get a read on them? One cylinder more black than others, or do they all look the same?

 

[eddiej]

That is dumping a lot of extra gas into your cats for sure. I had an LTD wagon that did the same thing, turned out to be a vacuum leak at the AC/heater control making it think it was lean so it called for more fuel.
On my 2.9 Ranger, the negative battery cable has a ground wire that has a connector (it is rather hidden and not the easiest to see it) which splits off into several other grounding points. That main wire was broken at the connector and it caused all kinds of issues. So I'd check the grounds as well.

 

[grumpy old man]

OK guys I am relearning how to cuss Fords. Long story short, I purchased a set of Bosch injectors to replace the Chinese that bought not knowing any better. Unfortunately again not knowing any better I had thrown out the originals so cannot try to cross them. By suggestion I checked with Ford to see if I could find the original part number by VIN only to find that the VIN is not listed. By application the number that the local Ford dealer gave me is E6SZ 9F593 A. Depending on who's website you are on this number does not fit. I checked with Bosch and they do not have a cross for that number, so either Bosch does not have an injector for the 2.9 or the number the dealer supplied is not correct. I do know that doing a google search on that part number it is listed for several Fords but none of the ads I have seen mentions it fitting a Bronco II. From what I have read supposedly the originals were repackaged Bosch which was typical for the era. I do remember that on more than one occasion waaaay back when, I would purchase an injector from a GM dealer only to find a Bosch box inside the GM box.

Does anyone know the way out of this maze, short of donating the car to a worthy cause?

I have almost for sure eliminated wiring as an issue. I managed to find an 89 Ford emissions manual and removed the entire under hood wiring loom spread it out on a large work table and did every pin point test listed in the manual. There is an in loom ground connector just outside of the connectors on the right valve cover which I checked carefully and just for good measure I soldered in a couple of extra ground wires.

I did find a kink in the return line above the fuel tank and thought OK found it, even though the fuel pressure was regulating at 33#. Replaced the entire return line and the regulator, fuel pressure now measures 35#, and the emissions are still through the roof.

 

[eddiej]

Hi GOM- There could be many puns dealing with exhausting the possibilities but Never Give Up!
Unburned fuel seems to be getting into your exhaust somehow being that the cats got so hot. This thread is pretty long, so I may have missed it, but have you verified that your valve timing is in sync with TDC on #1 cylinder? I know you said you set ignition timing to spec, but if the timing chain jumped prior to your setting ignition timing, valve opening/closing would be whacked in relation to TDC and you could still rotate the dist to make it match the timing mark on the damper.
Also, not to question your mechanical ability or skill, but are the plug wires placed correctly in the distributor cap as far as rotor's rotation and firing order? (It will run (poorly) with them in the opposite order(CCW vs. CW). Don't ask me how I know that.)
FWIW- When I resurrected our 88 2.9 Ranger after it sitting for 2 years, I got another set of injectors at the JY and sent 12 to an injector service outfit, told them to clean, refurbish, and match flow for the best 6 and send them back.

 

[grumpy old man]

As for my mechanical abilities let it suffice that I have been looking at open hoods for about 70 years. 25 of which were working for the most particular, and hardest nosed boss ever, my dad.

Mechanically the engine is fine, the raw fuel is getting into the exhaust via the cylinders. It is running horrifically fat for no apparent reason. I stopped at another Ford dealer and they gave me the same part number. I checked with Bosch again and this tech told me that Bosh does indeed show a cross for ford part number E6SZ 9F593 A but that part is not listed for a 2.9 Bronco II.

Alldata shows the injectors as either E56Z 9F593 A, or F132 9F593 A.

Soooooo, back to square one. What injector fits this 2.9 and who do I believe? It is this kind of s... that made me get out of the business in the first place.

 

[Tiha]

I have never played with injectors much on gas engines. I suppose though they certainly could be wrong. I would probably look on a place like the ranger station and see if those guys have figured out which injector to use.

Mis information is always an issue. Seems like the bronco is a step child. Everyone focuses on the F150. Or in this case the ranger.

I have worked on a Centurion or 2 and they are the same way. Some of it is bronco, some of it is F sereies. Oh but wait, because it is an 88 it somehow has '86 parts and '91 parts on it. So stupid.

 

[L\Bronco]

As for my mechanical abilities let it suffice that I have been looking at open hoods for about 70 years. 25 of which were working for the most particular, and hardest nosed boss ever, my dad.

Mechanically the engine is fine, the raw fuel is getting into the exhaust via the cylinders. It is running horrifically fat for no apparent reason. I stopped at another Ford dealer and they gave me the same part number. I checked with Bosch again and this tech told me that Bosh does indeed show a cross for ford part number E6SZ 9F593 A but that part is not listed for a 2.9 Bronco II.

Alldata shows the injectors as either E56Z 9F593 A, or F132 9F593 A.

Soooooo, back to square one. What injector fits this 2.9 and who do I believe? It is this kind of s... that made me get out of the business in the first place.

Hey Grumpy, sorry you are still fighting this one. I did a little research and you are right, the injector part number is tough to nail down for the 2.9. Too high of a flowrate can certainly manifest the way yours is. Ill keep digging.
I want to point you back at that ground, (Blk\Grn) wire at the HEGO sensor,
I have had this a couple times on old OBD-1 Fords and the result is Immediate unexplained rich.
I know you added some grounds already, maybe solder in a ground on the Blk\Grn right at the sensor connector and run to battery ground, just to be sure.
Hope that helps
Cheers

 

[grumpy old man]

Already did it. Going to be a while before I get back to it, like I don't have enough problems in my life I am now down with Covid.

Bosch recommended GB reman. I checked with them and they have OEM reman injectors for the 2.9 both Bosch and Denso which seems rather strange since Bosch stated that they do not make an injector for this application. For $60 it might be worth a try but like a damn fool I threw out the original injectors and the core value is $30 each.

Oh well, back to bed

 

[L\Bronco]

Already did it. Going to be a while before I get back to it, like I don't have enough problems in my life I am now down with Covid.

Bosch recommended GB reman. I checked with them and they have OEM reman injectors for the 2.9 both Bosch and Denso which seems rather strange since Bosch stated that they do not make an injector for this application. For $60 it might be worth a try but like a damn fool I threw out the original injectors and the core value is $30 each.

Oh well, back to bed

Oh man, sorry to hear that, please take care.
For the record, Bosch originally made the injectors for ford.
I think that making sure the injectors are correct is definitely the most important part.
I fought with that very thing on my 79 restomod, for a while. It is really close now, but still off a bit.
Get better and we will help you through the rest of the battle with the Bronco.
Ill do some more digging on the correct flowrate for your truck
Cheers

 

[grumpy old man]

Just just got done with 4 does in the days in the hospitatale with a capsilapped lung. Please excused spelling and sentience as I my brain is functioning at about 30%. This Covid is really bad sh..

Anyway a friend of a friend knows the obd1 stuff and is willing to do thing this thing but is woderinng if there is somewhere I can beg, borrow, steal, rent or by any other means obtain the use if a 5 gas analyzer because it will make the job much easier.

I just spent 45 min composeing a message do my Dr. with the hospital discharge instructions and 20 min composing this and I am exhausted. I am gooing back to bed.

Just FYI apparently Bosch injectors are color coded. The ones that were supplied at a Bosch distributor and now in the car are light mint green.

 

[Tiha]

They are color coded. Any idea what the original color was?

I did find that Stock 2.9 injectors are 14 lb/hr.

Then i found this.

grey 14#
orange 19#
lt blue 24#
red 30#
dk blue 36#
lt green 42#

also found this
"each PCM(ECM) is indeed programmed with engine size, injector size and Fuel pressure expected

And when cold it does run without O2 sensor feedback, Open Loop
Once the O2 sensors are hot enough(650degF), 3 to 4 minutes of run time, the PCM will go into Closed Loop as it now has Feedback on the air/fuel ratio needed for calculating best fuel mix

In closed loop the PCM would calculate open time for each injector, that calculation is 0 STFT(short term fuel trim)
Calculation is based on RPM, load, MAF(air weight), fuel pressure and injector size
If O2 shows "rich burn" not enough oxygen, then computer reduces injector open time
If O2 shows "lean burn" too much oxygen, then computer opens injector longer
This takes 2 or 3 seconds once Closed Loop starts

If injector open time is 20% lower or higher (-20stft, +20stft) then computer will set a rich or lean code, but engine was never actually running lean or rich, except at FIRST COLD START

The computer also has LTFT(long term fuel trim) this is an average of STFT, so if you had larger injectors, and computer needed -20stft to get correct burn, then LTFT would be -20
So at NEXT cold start computer would use -20stft to start off

LTFT allows vehicle to age gracefully in normal use, lower fuel pressure, small air leaks, lower compression, all effect air/fuel ratios, so -10 to +10 LTFT allows computer to run engine better as it gets older, it doesn't have to constantly re-learn the failings of an aging system
If LTFT gets 15% low or high it will also set a code

So wrong size injectors, within reason, would just set lean or rich codes, but engine would run fine after FIRST start up/warm up"


Lets step back a minute. You are getting a lean code? But emissions test says it is running too rich?

That would mean the lean code is telling the PCM to send more fuel which is failing the emissions test.

I wonder if there is a way to add a resister to bias the O2 Sensor. Make it read less lean.

 

[eddiej]

Maybe there's your problem GOM. According to TIHA's info above, you have injectors that could be putting 3 times more fuel in that engine than its stock form would have called for (14 vs.42) . I'd be surprised if the OBD1 fuel tables could adjust (shorten) the 42# injectors pulse width for that much of an overage or volume.
FWIW- 60+ years taught me to never throw any of the old parts out until I'm sure the new ones fix the problem.

 

[grumpy old man]

Yes Eddie. I know that lesson and the only thing I have thrown away is the original injectors and sparkplugs. Wouldn't you know it. While I am throwing all kinds of stuff at this thing I have now come full circle in my thinking and am starting to take another look at the ECM. I am remembering in another lifetime I was helping my brother in law with one of the turbowed 4 cylinders in a shay model A. It ran fine until it would start to warm up a bit and then would run like garbage. after fighting it for a couple of days dawn finally broke over me and I reached down to the O2 sensor plug and disconnected it. It instantly smoothed out and ran fine. He had a friend that had a turbowed 4 cyl mustang, they took the ECM out of the mustang and put it in the shay and cured everything.

This thing went from almost passing, it was a little out on the 15 MPH test and passed the 25 MPH test to emissions that increased over100 X literally overnight with no change but about 5 degrees change in timing.

The O2 sensor plug is almost impossible to reach so as soon as I have rejoined the world of the living I am going to find the necessary plugs to make a long extension cord for the O2 sensor, put a probe in the exhaust so I can unplug it to see what happens.

I did find some information that could be useful. Alldata shows injector numbers that are discontinued for the 2.9. E5TZ9F593A and F13Z9F593A. These are both discontinued numbers that an internet search shows fitting the 89 2.9, and may be original part numbers. Going to check with Bosch in the AM and see if they have a cross for them. right now I am going back to bed. My body does not like being vertical.

 

[Tiha]

hate to say throw an ecm at it, but you never know.

I have a diesel that I hadn't driven in a bunch of years. When I got it going again it seemed so gutless and way worse than I ever remembered. It has bigger injectors, cutsom chip, lots of performance mods.

Anyway I had this old banks chip that I loved the drive ability of, even though it wasn't near the power level of a custom tune. But I was so unhappy I put it in and took my custom tune out.

It was a completely new truck. turns out my custom chip was bad. Truck started and ran perfect. Didn't smoke or shift funny. you would never think anything was wrong, But oh boy it sure was.

they can sneak up on you like that.

 

[grumpy old man]

This would be the third ECM I have encountered that just all of a sudden for no apparent reason started running **** over a period of more years than I want to think about. All Fords. so as you say who knows.

The thing is that it is running fine no constant codes, it will throw a 14 that disappears on restart, but shows nothing that could be causing emissions more than 100 times over allowable and I have replaced almost everything else. So at this point what is another $180.00?

 

[grumpy old man]

I am just on the verge of rejoining the world of the living. Been doing a lot of research on injectors and ECM's. What I have found is that my issue is beginning to sound a lot less like the ECM. The injectors however......... Was finally feeling a little better yesterday and decided to actually have a look under the Bronco hood. With a little effort I was able to get a number off of one of the injectors and found out it fits a BMW. Without getting into my feelings about Germán cars it obviously does not even come close to Bronco specs. Obviously The first order of business is different injectors. The earliest Ford number I have been able to find that ford lists as fitting the 89 2.9 is F13Z9F593A, a long since discontinued number. It does cross over to Motorcraft CM4722, which also appears to be discontinued.

There are several websites which show new injectors from manufacturers I have not heard of, and going to an actual injector store obviously is not the answer, that is where I got the Bosches that are in there. So does anyone have any experience with something they have used that actually worked?