New fuel injectors

[Trstno1]

Ok-

So I have done a lot of engine work this winter but am still not happy with the way the engine is running. It still has a bit of a rough idle and the engine vibrates the car more than it should. I had my injectors professionally cleaned but am still not completely happy with how they are spraying. After I have tested all other items that could be causing the symptoms I am am observing, everything checks out. The only thing left that I can think it to replace the injectors. All six at the same time with new ones.

I have replaced the following parts:

Cap
Rotor
Spark plug wires
Spark plugs
All fuel lines with SS
DMCH fuel sender combo unit
Fuel filter
Vacuum lines
Professionally (Hervey) cleaned injectors
Idle control valve

I have completed the following work and tests:

Completely cleaned out the fuel tank prior to new pump installation
Replaced fuel filter, andall fuel lines except hard lines
Replaced spark plugs- all gapped at .024-.026
Readjusted CO for +\- 5 over 40 Dwell when warm
Tested spark plu wires with a timing light for spark: all good
Tested timing: dead on per manual for cylinder #1
Tested cold start valve: works
Thermotime switch: works
Idle control valve: definitely works
Frequency valve: works
Tested control/primary/rest pressure: all nominal (cold start control pressure w/o WUR hooked up a little high at 30 PSI)
Replaced all vacuum hoses with new set
Checked and rechecked vacuum connections: looks good ( gauge for vacuum test currently on order)
Car idles at 775 within 1 minute after start



The problem: it just idles a little lumpy. Lumpy enough that you can feel the vibration while sitting in the drivers seat. That lumpiness seems to dissipate with throttle acceleration, but comes right back at idle. I keep thinking I may just have tired injectors.....

Now, I've checked with all the vendors and have checked on the prices on new injectors. Are the vendors still selling original injectors ending 022 or are they selling 013's or are they selling Chinese knock offs? I was also curious if anyone has purchased Bosch injectors with a different number? It seems after a little research on the net I have found other injectors that claim to work on the Delorean. The one's on eBay are fj537's, part geeks has a Bosch 1238-07208586 they claim is for a Delorean, and O'Rielly auto parts has injectors with a part number of 62708 and 57711 respectively.

I guess my question is this: which of these are the ones made in China? Also have anyone had any luck running injectors from an 83 Volvo 760? Must I purchase these things from one of the vendors or are there other injectors that will work? I really just want to realize a "smooth" running Delorean.

Help! Any suggestions would be great! What do you guys think?

Thanks for your time...

[DMC5180]

Have you ever had the chance to sit in another running Delorean for comparison? Just saying one persons perceived lumpiness might be normal for an Odd fire PRV. However a cylinder compression test/leak down might be worth while.

Many years ago I installed I set of (DMCH) Nology ignition wires that were built to incorrect specifications for setting the Spark plug boot height. The boots were in the plug wells but the wire terminal was not physically in hard contact "Snapped down" on the spark plug. The engine fired up and ran like a lumpy 350 chevy. Once it was determined I had the defective wire set, I was able to reposition the boots and it ran Normal after that.

[Trstno1]

Have you ever had the chance to sit in another running Delorean for comparison? Just saying one persons perceived lumpiness might be normal for an Odd fire PRV. However a cylinder compression test/leak down might be worth while.

Many years ago I installed I set of (DMCH) Nology ignition wires that were built to incorrect specifications for setting the Spark plug boot height. The boots were in the plug wells but the wire terminal was not physically in hard contact "Snapped down" on the spark plug. The engine fired up and ran like a lumpy 350 chevy. Once it was determined I had the defective wire set, I was able to reposition the boots and it ran Normal after that.

I sure wish I had another D's engine to compare to. Unfortunately Delorean owners in Alaska are few and far between. So few matter of fact that if I were to see one it would be paramount to a UFO sighting....

Though I must admit that I often wondered if my idea of smooth running was never the way a PRV ever ran in the first place. The only thing that really bugs me is the occasional shimmy of the engine that produces just enough of a vibration that I can feel it in the drivers seat. I figured I always cracked up the lumpiness to a dirty fuel system that just needed a complete sorting. I was hoping be able to get rid of it by doing all the work I completed. No such luck..... Don't get me wrong, it runs much better after the work just not as perfect as I assumed it would.

[Bitsyncmaster]

The PRV is a funny engine. Some people have a "hunting idle" and others do not. Many have tried to stop hunting idle and most never get all of it to stop. Everything needs to be perfect and even then some will hunt.

[Trstno1]

The PRV is a funny engine. Some people have a "hunting idle" and others do not. Many have tried to stop hunting idle and most never get all of it to stop. Everything needs to be perfect and even then some will hunt.

Well, today I'll be conducting various vacuum tests.

I'll to the warm control pressure test to prove once and for all if the WUR is operating wonky.

Im pretty positive my vacuum lines are connected correctly and good since they are brand new, also I'll conduct a smoke test and see what else may be leaking. I should be able to just pull the air box, block off the meter plate and inject smoke into the air breather hose right?

I'm thinking that my small issue has got to be a little vacuum leak somewhere..... Though I haven't ruled out all specific vacuum components yet.

This morning I bench tested the vacuum delay valve and leaked from 16Hg to 8Hg in just over 16 seconds. That seems high. I always thought when these valves go bad they leak quicker than the manuals 10+- 2 sec? Do I have a bad valve or a really good one?

I also tested the vacuum advance off of the distributer. It holds a vacuum, so that's good!

Does anyone know how to bench test the vacuum solenoid behind the intake manifold?

[DMC5180]

Just thought, you might check too see if the full throttle enrichment switch is "open circuit". This is a delicate switch in that if over tighten the tiny mounting screws it can bind the internals. If you push on the flap and let go it might not release. This scenario adds extra fuel under idle and can make the engine run a little rough.


Dennis

[DMC5180]

Curious, did you import your D or was it already in the area?


Dennis

[Trstno1]

Curious, did you import your D or was it already in the area?


Dennis

The full throttle enrichment switch is good. As for the car, it was in the state for at least 10-15 years prior to my ownership. Where it was before then I'm not positive. It was sold in California originally and eventually made it to Alaska...

[hmcelraft]

You could indeed have a vacuum leak. If you could get someone to put a smoke machine test to the engine that could tell you a lot. You might be surprised.

The places for a leak big enough to cause a miss are numerous. However, common ones are - the idle motor tubing, the paper gaskets for the throttle plate tubing, the idle valve plugs located just before the throttle plates may not closed, and the intake manifold seals (O rings) at the heads could be compromised. Also be sure to check the vacuum feed at the back of the manifold that supplies the power brake booster, etc. That line is metal under the body and it could be damaged (you didn't say how the power brakes work).

I have sprayed carb cleaner on some suspect areas and get an engine change when the cleaner is sprayed on a leak. That is a dangerous option because of potential fire and I would not recommend it to the lesser experienced even with a big fire extinguisher handy.

[hmcelraft]

The hardest thing about using the air intake for smoke testing is getting it sealed somehow. A large size rubber glove can work if you're careful. Just clip a finger end off for input.

The delay valve spec you got is typical for OEM's - all of the ones I've tested were in your range - out of spec. The one I replaced them with were white/black and were ten second leak down. I didn't really notice any running difference re: cold engine acceleration however.

The vacuum solenoid is for the for the vacuum on/off at idle position and activates with 12 volts . A good 9 volt battery should activate it - just as 9 volts activates the relays.

[Trstno1]

The hardest thing about using the air intake for smoke testing is getting it sealed somehow. A large size rubber glove can work if you're careful. Just clip a finger end off for input.

The delay valve spec you got is typical for OEM's - all of the ones I've tested were in your range - out of spec. The one I replaced them with were white/black and were ten second leak down. I didn't really notice any running difference re: cold engine acceleration however.

The vacuum solenoid is for the for the vacuum on/off at idle position and activates with 12 volts . A good 9 volt battery should activate it - just as 9 volts activates the relays.

I just completed a smoke test today but found absolutely nothing. Everything seems tight. I might just need to spring for new injectors.....

[Trstno1]

So, back to the injector questions.....

Any takers?

[Ryan S.]

So, back to the injector questions.....

Any takers?

If you are asking where to get a new injectors, you may want to ask Rob G. Sounded like he has genuine products.
Other option is to get some used ones from DMCMW.

You can also post video of your injector spray pattern test. I am sure someone will respond.

[Trstno1]

I've checked with all the vendors and have checked on the prices on new injectors. I have also checked with other sources such as large automotive box stores. The price difference between the two is large so I was wonder is anyone could shed some light as to why.

Are the vendors still selling original injectors ending 022? If not, what Brand and part number are they actually selling? For the premium price do they have a stellar warranty and/or low out of the box failure rate?

I was also curious if anyone had purchased Bosch injectors with a different number? It seems after a little research on the net I have found other injectors that claim to work on the Delorean. The one's on eBay are fj537's, part geeks has a Bosch 1238-07208586 they claim is for a Delorean, and O'Rielly auto parts has injectors with a part number of 62708 and 57711 respectively that work on either a Delorean or a 83 Volov 760.

Im not trying to take business away from the Vendors, I guess I am just questioning such a premium price if the injectors are available elsewhere for literally half the price.

What do you guys think?

[hmcelraft]

Why not just pop out the injectors and see what the spray pattern and flow of the injectors looks like? You should be able to do that while everything is still hooked up to the car.

[Trstno1]

Why not just pop out the injectors and see what the spray pattern and flow of the injectors looks like? You should be able to do that while everything is still hooked up to the car.

I did.

They injectors spray fuel, but some kinda spray to the side while at least one oscillates. They are definitely not perfect. I think I have 3 that are what I would consider good. When I was rebuilding the engine from the VOD experience I had sent in the fuel injectors to a vendor that offers "professional" cleaning. Unfortunately, when I got them back and spray pattern tested them I wasn't really impressed with the results. They looked new on the outside but performed in pretty much the same manner as when they left. Sorta bummed.... I put them in anyway simply because I had nothing else.

Ever since then, I've been chasing this lumpy running motor. All other components check out. So I'm down to the fuel distributer, fuel injectors, or a valve/piston issue. Since the fuel injectors seem to be the cheapest parts I thought I would start with them.

Ill have to post a video of how it runs. The motor does start and run. But it's lumpy and vibrates the car, definitely a slight miss. I'm almost at my wit's end with it. Something that has started off as an adventure has got me close to going insane. But with so much time, money, blood, and sweat invested I have to see this through.

Any thoughts as to new fuel injector quality and where to obtain them from?

[Ryan S.]

Something that has started off as an adventure has got me close to going insane. But with so much time, money, blood, and sweat invested I have to see this through.

+1. Often feel the same way. Especially right now.

[hmcelraft]

I did.

They injectors spray fuel, but some kinda spray to the side while at least one oscillates. They are definitely not perfect. I think I have 3 that are what I would consider good. When I was rebuilding the engine from the VOD experience I had sent in the fuel injectors to a vendor that offers "professional" cleaning. Unfortunately, when I got them back and spray pattern tested them I wasn't really impressed with the results. They looked new on the outside but performed in pretty much the same manner as when they left. Sorta bummed.... I put them in anyway simply because I had nothing else.

Ever since then, I've been chasing this lumpy running motor. All other components check out. So I'm down to the fuel distributer, fuel injectors, or a valve/piston issue. Since the fuel injectors seem to be the cheapest parts I thought I would start with them.

Ill have to post a video of how it runs. The motor does start and run. But it's lumpy and vibrates the car, definitely a slight miss. I'm almost at my wit's end with it. Something that has started off as an adventure has got me close to going insane. But with so much time, money, blood, and sweat invested I have to see this through.

Any thoughts as to new fuel injector quality and where to obtain them from?

Have you checked to make sure the "plunger" in the injector body is completely free and moves properly? That's about the last issue I can think of before replacing the injectors. I would call Rob Grady and get his advice. He can be sure you get a quality injector. I'm surprised that Hervey didn't alert you that he could not get the injectors to work properly. Professionally cleaned injectors usually have a high rate of success.

[DMCVegas]

It sounds like you've got a problem with an incomplete burn. A "hunting" engine is different. That's when your idle keeps going up and down as the car revs on it's own. That's the LAMBDA emissions system fighting a vacuum leak. Don't bother with that right now.

My guess is your engine has a lumpy idle with a slow throttle response. You press the gas pedal and it goes "vvvvvvvvvvvvrrrrrrrrrrrrrRRRRROOOOOOOOMMMMMMMMMMMM M!" with a flat increase in RPMs before they suddenly shoot up really fast. That is caused by incomplete fuel burn inside of your combustion chambers, which in turn is the result of one of two things. First item is the Ignition System, and more specifically a weak spark.

The first thing to check is that you don't have bad Ignition Wires. ONLY use BOSCH brand made for the PRV. I've found that cheaper brands split easier and cause leakage. Other than the MSD Blaster 2 Coil, the only other successful one I would reccomend is the OEM BOSCH unit. And then too, make sure you're running the proper BOSCH spark plugs with the correct gap per your Workshop Manual.

Second item is fuel. If you have injectors that are not properly atomizing fuel, that means that it doesn't burn completely and properly, which can give you that lumpy idle. Which I then read this from you:


They injectors spray fuel, but some kinda spray to the side while at least one oscillates. They are definitely not perfect. I think I have 3 that are what I would consider good. When I was rebuilding the engine from the VOD experience I had sent in the fuel injectors to a vendor that offers "professional" cleaning. Unfortunately, when I got them back and spray pattern tested them I wasn't really impressed with the results. They looked new on the outside but performed in pretty much the same manner as when they left. Sorta bummed.... I put them in anyway simply because I had nothing else.

Yeah, that's not acceptable. Here is the guide for spray patterns:


http://rennlist.com/forums/attachments/924-931-944-951-968-forum/531697d1303827474-wtb-bosch-universal-crush-filter-fuel-injector-spray-pattern-c-specialtauto.jpg

The problem with these "cleanings" is that they'll get rid of things like gum and varnish, and that's about all they'll do. The two other problems that you can have with a K-Jetronic Injector will be a worn spring on the internal Needle Valve. That can cause things like an unbalanced injector set when it opens at the wrong time, as well as when it now sprays way too much fuel and runs that cylinder rich, it throws the engine into a tizzy, and of course then the LAMBDA system is fighting it, and it's a mess. The other problem is rust. Inside of these injectors you can have other types of corrosion that can form on old injectors over time. Even if you placed one of these injectors into one of those sonic cleaning machines, there is still a filter screen and the spring valve where crap gets trapped and can't come out.

The only way that I could recommend you clean injectors would be to buy/build your own injector tester, or find a BOSCH shop that has the tools and can perform the same service. Run solvents through them and see if they clean up. THEN you can also use the same tool to verify the internal spring is good. If they never spray clean, or they open at the wrong pressure, throw those injectors away.

But for your car, you now KNOW you have a problem with the injectors. Order some up from a different vendor.

[Trstno1]

Have you checked to make sure the "plunger" in the injector body is completely free and moves properly? That's about the last issue I can think of before replacing the injectors. I would call Rob Grady and get his advice. He can be sure you get a quality injector. I'm surprised that Hervey didn't alert you that he could not get the injectors to work properly. Professionally cleaned injectors usually have a high rate of success.

What plunger are you talking about? The one in the fuel distributer? or the actual plunger on the bottom side of each injector?

As far as not being told they didn't work correctly......yeah I'm surprised I wasn't told either.

[Trstno1]

Has anyone tried the Bosch 62708 fuel injectors for our cars?

[Horsebox]

I had this dilemma when I replaced my injectors. I can't remember whether it's the 022s that are stock and hard to come by or the 013s. In the end I had no choice but to go with whichever of the above part numbers was available. The car runs fine, closed loop fuelling, after installing the new injectors.

I hope that makes sense!

[Horsebox]

Or another way....based on my experience either 022s or 013s will be fine! :-)

[Horsebox]

I think the 022s are the DMC part number. 013 is Volvo. I'm pretty sure I'm running 013s, since that was all I could get at the time. And it's fine.

[hmcelraft]

I was referring to the plunger on the fuel distributor.

[Trstno1]

Or another way....based on my experience either 022s or 013s will be fine! :-)

Ok-

Well it looks like DMCNW has 022's that I'll hopefully be able to order here soon. I guess I was just hoping that there were some owners who had tried the alternatives....

[hmcelraft]

Years ago I replaced all of the injectors in a DeLorean of mine with 13's because my parts dealer said they were the numbers that the Volvo B28F calls for (among others like the B27, etc.). Ran great and the car went back to the great gas mileage I got originally. They worked well for the next 50,000 miles and when I sold it. I'm looking for the old 22's in my stash (I believe I still have them) because I think I have an injector going bad in my current DeLorean (22's) and I want to fix it.