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New injectors, running poorly

4K views 30 replies 6 participants last post by  JCart 
#1 ·
New injectors, total buzz test failure
Hello all. First time posting to the site. I have a 1997 F250HD 7.3 manual ZF5 short bed crew cab with 207,000 miles. I have owned the truck for 4 years and roughly 40K miles. Until recently the only engine mods have been the AFE cold air intake and MBRP 4" turbo back exhaust with cat delete and 3" downpipe. I change the oil every 5K miles and always run Rotella T4 15W-40 and Wix XP oil filter. I also change the fuel filter every 10K miles with Wix filter. Overall I think the truck has run well considering it is 22 year old. Cold starting seemed to be the only nuisance. It is my daily driver and is parked in the garage. When starting in the morning if I drove it the day before it would fire up pretty quickly, but if left for a few days starting up would take quite a bit of cranking and lots of black to white smoke. Once running idle seemed to be decent but not great. All of this i chalked up to the quirks of an old diesel truck.

A few weeks ago I decided to see if I could improve the cold start. I inspected the wiring harness connections and found the pigtail connections on the rear of the motor were fried. Looked to be the glow plug connections for #5, #7 and #8 were all bad. Instead of just replacing the connectors I decided to jump in and replace the injectors, valve cover gaskets, glow plugs and pigtails. I ordered 8 Full Force Stage 1 180cc injectors, 2 new Alliant valve cover gaskets/harness, 4 new Alliant pigtail connectors, and 8 new Motorcraft glow plugs. To run the upgraded injectors I also purchased the PHP Hydra chip (no chip had been run on the truck before). Last weekend I installed everything without issue. Truck fired up super fast and seemed to be great even after sitting for a few days.

Then I did some test drives and noticed some issues. At low speeds all seems well, First to second shift good, second to third shift good, but above that the truck shifted really funny. When accelerating in third gear up above 1500 rpm and then engage the clutch to shift the rpm's would drop drastically down below 400. If I tried to engage the next gear as normal the truck would "clunk" as if it was hesitating. This was true in the next shift forth to fifth as well. Also if I waited to engage the next gear the rpm's would drop below 400 and bounce back up to 650. This would happen about three times until the engine leveled off at normal idle rpm of 650. If i keep the shift points below 1500 rpm it doesn't seem to be as bad, but if I step on it and get above 1500 - 3000 rpm it is really bad. Additionally if i really step on it in the lower gears, say 3000 rpm shift from second to third there is no issue and shifts perfectly.

So here is what I have done so far to fix the issue.
- replaced EBPS (both the sensor and the tube. I made sure to clean out the bracket at the sensor and the connection to the manifold as well.
- checked ICP sensor and found some oil in the connection. Replaced with new sensor.
- opened valve covers again and re-torqued the injector hold downs (all good)
- visually inspected wiring and connections (all good)
- replaced CPS
- OHM tested the injector wiring and harness at the injectors all the way back to the IDM. (all ohm tests were good and all continuity checks were good)
- buzz tested injectors using OBDlink MX+ wifi dongle to iPhone app FORScan.

Here is where I really get confused. the buzz test runs and all the injectors buzz appropriately and sound the same. I did this with the motor both warmed up and the next morning totally cold. Each time the test comes back with failures to all injectors. Here are the codes...

P1271 to P1278, P1293, P1294, P1298 all failed.

I also removed the Hydra chip to see if that made a difference. The buzz test results are the same but the truck did seem to run better, but with less power of course. The shift issues also seemed to clear up as I did not get the rpm flutter between shifts.

The only other thing I can think of is a failing IDM. Before I keep throwing money at the issue I was hoping there were some more diagnostics I could do. Any help would be greatly appreciated.
 
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#2 ·
With all those codes, I would try an idm out. See if anyone will swap you for a test or run to the junk yard and buy a cheap one. I might of missed it but did you change the pigtails too?
 
#3 ·
Thanks. Looks like I will be hitting the junkyard today. Just so happens the one close to me just received a 94 F250 7.3. Would an idm from that work in my 97?

And yes I replaced the pigtails as well.
 
#4 ·
Lotsa upgrades nice.... the CPS and ICP are Ford OEM parts yes? Sometimes the “new” none OEM replacements will give you grief.

Are you running stock HPOP and can you check HP oil to ensure you have enough, I’m thinking you are running out of HP oil.

Have you checked your fuel pressure and is it stock or electric, most injectors like around 62-65 psi at idle. If stock you can check via the schrader valve. Do a search on shimming fuel pressure regulator (stock) as you can increase fuel pressure with this mod. Lastly, I’d run a boost fooler in-front of the MAP sensor. MAP sensor gets confused when over boosted above 24 psi and will revert to ECM fuel tables, which can cause problems with aftermarket tunes. Boost fooler can be made or RiffRaff Diesel sells them too, limits boost seen by MAP sensor to 21-22 psi.
j
 
#5 ·
Yes, the ICP, EBPS and ICP are all Ford OEM.

I am running a stock HPOP. I thought about checking the HPOP oil level but someone prior to me stripped out the filler nut. I was going to do a search on how to get it out when stripped. I am also running the stock fuel bowl (not electronic fuel). I will do a search on how to check the fuel pressure and see about the shimming mod. I planned on doing the boost fooler later this month.

It seems to me that all of these items above are only addressing the RPM flutter with the chip in at higher RPM shifts. I currently am running the truck without the chip and while it is shifting better and doesn't have the rpm issue it still seems to be running rough. This makes me think that there these are two separate issues. This is further backed up by the total failure of the buzz test.

This brings me back to the IDM. Junkyard run was a failure today. Their inventory search had an incorrect listing and did not have a 7.3. Unless anyone has other ideas I am going to have to drop some more coin on an IDM this week.
 
#9 ·
Yes, the ICP, EBPS and ICP are all Ford OEM.

I am running a stock HPOP. I thought about checking the HPOP oil level but someone prior to me stripped out the filler nut. I was going to do a search on how to get it out when stripped.
What I mean by enough oil is whether the output of the HPOP is adequate to drive injectors. If you don’t have access to Auto Enginuity or a scanner that will monitor pump pressure you could always hook up a liquid filled gauge into any of the HP oil plugs on the head with a length of high pressure hose and monitor. I have one in my shop I use periodically it’s a 5000psi gauge and 5ft length of high pressure line.

In regard to fill plug on top of HPOP Reservoir you can always undo the oil pressure sensor on the passenger side top of Reservoir. Can also helicoil the oil plug itself, but kind of a hassle as you have to remove the Reservoir. If the fill plug Allan head is stripped just pound a larger Allan socket into the hole and undo it, the plug itself is an odd metric thread, RiffRaff has plugs I think.
j
 
#6 ·
Just so you know. Any idm from 94.5-03 will work. What did you use to connect the pig tails to the engine harness? I would go and check all those connections.
I too think there is two issues but tell you get all the codes figured out, I wouldn't be messing with the shifting issue. It could be a few different issues but we will get to that when it's running good.
 
#8 ·
I used Alliant harness and Alliant pigtails. I soldered the pigtail wires to the engine wiring harness. I believe the connections are solid and accurate but started to doubt myself, so last night I went over all the wiring again back to the IDM and everything checked out.

BTW... thank you all for this feedback. I LOVE my truck and really want it to run well.
 
#10 ·
Thanks JCart. I don't have access to Autoenginuity or a scanner that will read pump pressure. I will do the pressure test with the gauge and high pressure hose. What psi should it read?
 
#11 ·
So you will need minimum of 500 psi to fire injectors. I have just installed FFD 205/30s jectors and with stock HPOP, I’d get 3000 psi on initial fire up then would settle down, so you should see a range of pressures from 500 minimum to 3000psi plus.

I was testing an aftermarket pump, which I’ve sent back for to manufacturer for testing and installed the stock one with know good IPR for above pressures. I didn’t drive mine just tested and when I saw 3000, I knew pump would be ok to use, for now. If you get a long hose you can leave the hood to safety catch and put gauge under wiper and drive it around to monitor pressure. Recommend a liquid fill 0-5000 psi gauge and make sure you get a swivel on the gauge end so you can twist it to face where you want. I used ORB to JIC from head then JIC fitting in hose and had it made up at my local hydraulics shop. Get a couple ORB to JIC into head fitting with additional JIC caps in this way you can pull the stock plugs (ORB) install the ORB to JIC fitting and test pressure to each head. Remember to test each respective head you must also plug the other head at HPOP outlet right. So you’ll also need JIC cap for the HPOP and plug for that line. Hope that makes sense. Lastly you can also test pump on it’s own too right, by capping one line (right at pump outlet) and gauge the other, this will test pump WITH IPR. To totally isolate pump (I.e., without IPR inputs), you can get a plug from RiffRaff that replaces the IPR.
j
 
#12 ·
Cainbr,

The wire that you soldered onto in the original wiring harness - were they in good shape (bright and shiny copper)? I'm leary of soldering onto older wires as the oxidation tends to make it very hard to wet out the solder (even with good flux) on the wires. It is possible to get an electrical connection that tests good with a voltmeter, but when placed under tension (120 volt IDM pulses for example) more or less looks like a huge resistor.

Cj
 
#13 ·
JCart - thank you for that explanation on testing the HPOP pressure. The procedure makes sense and was well said. I will give it a shot this weekend.

cjfisher - I believe the exposed wire from the engine harness was in good shape and looked shiny. I may open one connection up just to make sure. Is there a way to test if they are acting as a resistor?
 
#14 ·
I figured out how to get my scanner to read ICP pressure (Forscan lite for iOS with OBDLink MX+). I ran this without the chip.

Idle @ 650 rpm...
587 ICP psi (normal range 575-600)
12.50% IPR duty cycle (normal range 11%-14%)
14.3 EBP psi (normal range 14.3-14.4)

Under Load - WOT...
2602 ICP psi (normal range 2450-2700)
35.16% IPR duty cycle (normal range 35%-40%)
22.9 EBP psi (normal range 28.0-32.5)

I found the ranges listed above from a diagnostic PDF put out by Oregon Fuel Injection. I am going to put my PHP Hydra chip back in tonight and run the same test to see what numbers I get. Also did a buzz test again and produced same results and codes as above.
 
#15 ·
CainBr,

With those numbers you probably have good connections. Time to find a spare IDM.. The only other thing I can think of is a mis-wire in the harness.. IE you wired the injectors to the glow plug ground or something, but you have checked the harness - twice now.

Cj
 
#16 ·
Update... I ordered a fuel rated pressure gauge and 90 deg schrader valve to test my fuel pressure. It bounces a bit but ranges between 55psi and 65psi at idle which seems good.

I was not able to test under load as my hose is not long enough. Ordering a longer hose to do this. Also I have not re-installed my chip yet so all this diagnostic work is at stock to try and limit variables. The main issue I am still chasing is overall rough idle/poor running. I am still throwing all the same injector codes and IDM codes as before so I still think this issue is the IDM. Through some connections I was able to track down a known good IDM and will be meeting up on Monday to install and test (fingers crossed). If IDM failure is confirmed I planned on ordering the Swamps Hi Voltage Hi Frequency IDM.

I will continue to update until final fix is reached. Thank you all again for the help. It is greatly appreciated.
 
#17 ·
Diagnosed over weekend a bad alternator. Seemed to be running fine and all my scans and testing showed proper readings. Took the serpentine belt off to do something else and noticed the bearings were squeaking. Brought it in to the auto parts store for a bench test and it failed. Lifetime warranty replacement and new unit installed.

This morning was able to get my hands on the known good IDM and installed the unit. Fired the truck up and immediately knew there was an improvement. Shut down and ran buzz test and all passed. No more codes!!! Buddy let me hold on to good idm while waited for mine to arrive.

Did some research and ended up ordering the high voltage high frequency IDM from Diesel Technology of Chattanooga from Full Force Diesel. Also ordered a high pressure oil crossover. I will report back once installed with the chip back in at full power.
 
#19 ·
Whoo hooo, Nice! Good to get passed the hurdles I’m sure, can be soooo frustrating at times, happy you have it resolved. As noted above keep us posted on the HV IDM mod.
Cheers,
j
 
#21 ·
Updates... Since my last update I have been using the borrowed IDM and the truck has been running overall much better. I am still not throwing any codes and buzz tests are all passing. The issue that has not been resolved yet is the RPM flutter/hesitation when shifting. This only seems to happen after RPM's are reached above 1,800. It also seems to be more pronounced in shifting between 3rd to 4th. As long as I keep shift points below 1,800 RPM then all seems fine. I was wanting to start working on this issue when I received my new IDM.

Yesterday I received my new IDM from FFD. I upgraded to the High Voltage High Frequency unit from DTC. I installed the unit and immediately noticed a smoother idle and crisper throttle response. It just feels less rough. I also re-installed my Hydra chip and did some test driving and quickly found out two things. First off the RPM flutter is not changed with the new IDM. I wasn't really expecting any difference but figured it wouldn't hurt to throw some prayer in the mix, God knows I have thrown enough parts at it. The second new issue is a slipping clutch. I am guessing the clutch is original, or at least old, and with 209,000 miles and newly added power mods she just can't handle it. I can baby it and it holds, but if I get on the throttle it goes as soon as the turbo hits. Also once it started slipping there is now a definite vibration feeling coming from the clutch area.

So now I am prepping to do a clutch replacement. I ordered a South Bend Con OFE clutch kit rated up to 475hp. Once I get this installed I will focus on the RPM flutter issue which I believe to be fuel system related. More to come.
 
#22 ·
Thanks for the update, thinking you might need E fuel.... or do a search on shimming fuel regulator on here.
Cheers,
j
 
#23 ·
Trying to update to follow this until the end. I really love all the great info on the forums but the one thing missing is consistent follow-up to conclusion.

I agree on the e-fuel upgrade but will have to hold off for at least a few months. I am hoping that once I get my clutch fixed I can get a good fuel psi reading and then do the shim mod if needed. I am going to install high flow banjo bolts and the hpx When I drop the transmission to do the clutch. I also ordered a FPR rebuild kit to change out the filter at the bowl. Thinking this should increase overall flow and the shim will increase my psi. E-fuel will follow later.

I know it has only been a few days but I have to say that so far I am very impressed with the DTC high frequency high voltage idm. Not only is the engine smoother but I love how it helps with shifting the zf5. Not sure how to describe it...the injectors seem to stay on for half a beat longer than normal which keeps the rpm’s up and allows for quicker and smoother shifting since the rpm’s are better matched.
 
#24 ·
Banjo bolts are a waste of money.
 
#25 ·
Why are they a waste of money?
 
#26 ·
Stock banjos are good to well over 600 hp.
 
#27 ·
I installed RiffRaff high flow banjo bolts in the front of heads and used a custom high flow banjo to JIC fitting in the rear, with Russel hose and fittings to feed the heads. Noticed a difference.... nope, (we’ll not yet) but was going to e fuel anyways and wanted to do it only once. Not ran WOT runs yet with 205/30s and stock 7.3 E pump. Just need to install gauges, which are in transit now. Thing is cost wise they aren’t much, are quality pieces and easy to install.
 
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