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914World.com _ 914World Garage _ Trouble shooting injectors

Posted by: LanceW3544 Jul 29 2018, 02:38 PM

First of all forgive my lack of knowledge. I am not new to cars but I am new to 914s. I recently purchased a 1970 914 1.7L. with D. Jet. The previous owner noted that it ran last year but was not able to get running this year. The car is far from perfect but I hope to be a solid start for a EJ20 swap in the next year or so. I would love to get the 1.7 fired up to start taking care of of other issues I am not currently aware of.
So let me start discribing what I am seeing

Good Battery- Cranks over good and for a long time if needed
Fuel Pump- working well but does not shut off after 1-2 seconds.
New plugs
New wires
New cap and rotor
I check the fuel rail and I know I have fuel to the injectors.
I am able to fire the car up with starter fluid but ofcourse dies when it is burned off.
I have had it runnig several times but is not consistant.
I have check the grounds to the batter as well as the injector grounds. I don't know where to go next.

Any advice would be appreciated. As you explain your suggestion please don't use abbrevations as I am not framilar with them all yet.


Thanks
-lance

Posted by: mepstein Jul 29 2018, 03:25 PM

I send all our injectors to mr injector. Even if they work, he flow tests before and after cleaning and replaces the seals and hose. $17 each + 6 shipping. Then at least you know you are getting an even amount of fuel to each cylinder. If he can’t get an injector to flow correctly, there’s no charge. I sent him at least 150 injectors in the past couple years.

Posted by: Tbrown4x4 Jul 29 2018, 04:10 PM

What is your fuel pressure? Stock pump?

Check the lower set of points in the distributor. They provide a signal to the ECU (computer) to fire the injectors.

Posted by: Porschef Jul 29 2018, 04:38 PM

Really? Grand Rapids?

Hmmmm, idea.gif there might be a guy, uh, nearby, that knows a bit about 914's...

You might wanna start there...

Good luck.

Posted by: Bartlett 914 Jul 29 2018, 05:31 PM

plugged injectors or bad gas.

Posted by: worn Jul 29 2018, 05:35 PM

QUOTE(Bartlett 914 @ Jul 29 2018, 03:31 PM) *

plugged injectors or bad gas.

Bad gas, fuel pressure regulator not working, bad manifold pressure sensor, cylinder head sensor for temp, vacuum leaks. That would be my hit parade.

Posted by: LanceW3544 Jul 29 2018, 07:21 PM


Thank you everyone for your quick response. I am very grateful for the help smile.gif


mepstein- Great suggestion and for the price hard to beat. I want to try one or two more things before I send them out.

Tbrown4x4- Just replaced fuel pump with stock replacement. Not sure what fuel pressure is as I don't have a gauge hooked up inline. In regards to the points. They looked OK but to be honest I don't know what a bad set up points would look like. Can you give me any insight in that direction. Is there a way to test and see if the trigger points are sending a signal?

Porschef- Sounds like you know somone in Grand Rapids and if so... I would love a local contact


Bartlett 914- There was only a gallon or so of gas in the tank when I got it. I put in dry gas and also 4 gallons of 93 octane. Hopefully that would have done the trick for the gas situation and regard to the injectors I think we all can agree they might be clogged. I wish ther was a way to test and see if the injectors are even trying to open. I pull the fuel rail last night and turned the car over an nothing came out. Not a drop.

worn- Great luandry list of items. How do I test and see if the fuel pressure regulator or cyclinder head sensor is not working?




Posted by: Freezin 914 Jul 29 2018, 08:07 PM

QUOTE(Porschef @ Jul 29 2018, 05:38 PM) *

Really? Grand Rapids?

Hmmmm, idea.gif there might be a guy, uh, nearby, that knows a bit about 914's...

You might wanna start there...

Good luck.

He is referring to McMark, he is the owner of original customs, very knowledgeable and a great guy. He has advertisements and is a Administrator on this site. He is your guy. Good luck! And...... welcome.png

Posted by: Mark Henry Jul 29 2018, 09:07 PM

Down and dirty way to check on injectors is to remove them and with a pin press the pintle. Good they have a bit of give and you may even feel a slight click, seized they will be hard as a rock.

Posted by: 914 RZ-1 Jul 29 2018, 09:52 PM

I hooked a 9v battery up to the injectors to see if they made a clicking noise. You need 3 hands to do it, though! Put the injector (gently) in a vise and use your two hands to attach the wires.

I made a pressure gauge out of some tubing (fuel line at FLAPS*), small hose clamps and a pressure gauge to test fuel pressure (I think it was about $15 for the whole thing). I think it's supposed to be 29 psi on a 1.7.

I also recommend Mr. Injector. He's inexpensive and quick.

When my trigger points (not to be confused with the "points"-the "trigger points" are housed below the distributor cap) went bad, the car bucked like a bronco. It would turn over, but not start. I think you can check for continuity with a multi-meter. I'm not sure if these can be fixed or if you have to buy new or working used ones. Mine didn't look bad; they just didn't work.

(*Friendly Local Auto Parts Store)

Posted by: Dave_Darling Jul 29 2018, 10:11 PM

Your engine needs three things to run: Fuel, air, and spark.

An extra spark plug with the threaded part taped to a ground hooked up to one of your plug wires should show visible sparks when you crank the starter.

You can remove the injectors from one side of the motor (one M6 nut/10mm head each) and put the injectors into a jar. They should spray when you crank the starter. Or you can see if the tailpipe smells of fuel after cranking the starter for a while.

A compression test will tell you if you are getting air.

I would suggest making sure that all wires and hoses are plugged in securely to the right places. That's a very worthwhile first step...

--DD

Posted by: Chris914n6 Jul 30 2018, 04:02 AM

Unplug the coil - don't want any sparks for the next part. Unbolt the injectors from the manifold but keep them plumbed, you want to see if they are leaking or spraying. If you have no action check the trigger points. If still no action report back I'll write out the next steps.

You probably have someone local that does the injector cleaning and flowing, they all use the same piece of equipment. I've got 6 in Vegas....

Posted by: Bartlett 914 Jul 30 2018, 05:05 AM

So it runs with starter fluid. That speaks a lot. If you only had a gallon of gas and you add more without draining the old you may have left bad crap in the line. Water is a real problem! I have had several problems with water in the gas. Pull the injectors as suggested and point them in a jar to see it fuel is coming out. Go from there. Lots of luck.

Come to Garolds this weekend with or without the 914

Posted by: jonferns Jul 30 2018, 05:54 AM

Cruzin Performance is in Traverse City, MI. Just sent a set of injectors to him for flow test & cleaning; mailed on a Tuesday, back in hand by Monday. Great service

Posted by: LanceW3544 Jul 30 2018, 03:51 PM

Jonferns- How much do they charge for the injector cleaning.

I just jar tested the injectors. they did not spray at all. May cyclinder 4 just a tad. when I press on the pintle it sprays well.

Posted by: Dave_Darling Jul 30 2018, 03:57 PM

Still could be an unplugged MPS, or a set of unplugged trigger points. Don't automatically blame the injectors themselves--though they could indeed be the problem.

Check the whole engine bay for wires that are unplugged, or for ones that are not securely plugged in. Make sure the multiple ground point at the rear crankcase seam has six wires going to it, in three pairs.

--DD

Posted by: brant Jul 30 2018, 04:08 PM

QUOTE(LanceW3544 @ Jul 30 2018, 03:51 PM) *

Jonferns- How much do they charge for the injector cleaning.

I just jar tested the injectors. they did not spray at all. May cyclinder 4 just a tad. when I press on the pintle it sprays well.



The fuel injection points in the bottom of the distributor fires a pair of injectors at a time


did any of the 4 spray during the jar test, or none?

Posted by: LanceW3544 Jul 30 2018, 04:15 PM

I created all new grounds for the white injectors wires on the passenger side of the crank case. 6 white wires and one brown. To ensure they were grounded I also ran a ground from the battery to this area to make sure. still no spray. sad.gif

I only checked the driver sided as they are more accessable. I will check all 4 now.

what is the MPS sensor? I will check to ensure that is plugged in?

Posted by: jonferns Jul 30 2018, 04:57 PM

QUOTE(LanceW3544 @ Jul 30 2018, 04:51 PM) *

Jonferns- How much do they charge for the injector cleaning.

I just jar tested the injectors. they did not spray at all. May cyclinder 4 just a tad. when I press on the pintle it sprays well.


They charge $20/injector. They include painting the bodies and new injector seals.

Posted by: LanceW3544 Jul 30 2018, 05:27 PM

pull all 4 injectors and none of them are spraying. If I press on the tip and they spray no problem. Where to look next?

Posted by: Dave_Darling Jul 31 2018, 10:22 AM

Do you have a "noid light"? Or some other light that can react to very short power pulses? If so, plug that into an injector plug to see if the electrical signal is getting there when the starter cranks.

The MPS is the hand-grenade thing with one hose and a four-wire plug going to it that sits below the battery. The trigger points are in the base of the distributor, with the three-wire plug down in front of it.

Again, check all of the wires, plugs, and hoses. Make sure nothing has come loose.

--DD

Posted by: Chris914n6 Jul 31 2018, 03:42 PM

Next step is to trigger the injectors manually under pressure, jumper wires to the battery. I like to use gator clips on the injectors and tap, just tap, the battery post repeatedly.

A volt meter will pick up on the pulses from the ecu, but just barely as they don't react fast enough. A test light would work better, specially if it's LED. I'll need to read up on trigger testing, it's old tech in my world.

Fresh gas is the best cleaner of old gas. They will clean themselves with use, but not like new clean like the ultrasonic cleaning does.
Considering one of the members blew a hole in his piston on a freshly rebuilt motor from the injector spraying a stream instead of a mist, might be worth it to get them cleaned anyways.

Posted by: LanceW3544 Jul 31 2018, 05:56 PM

I was able to manual test the injectors. Directly powering them from the battery they all spray great! where to dig next?
ECU?
Relays?
Tirggers?

Thank you everyone for your time and participation. Very grateful

Posted by: Chris914n6 Jul 31 2018, 07:38 PM

Most likely injector trigger.

https://members.rennlist.com/pbanders/DJetParts.htm#troubleshoot

Posted by: Dave_Darling Jul 31 2018, 09:11 PM

Again, check all of the wires and hoses to make sure they are plugged in.

--DD

Posted by: LanceW3544 Aug 1 2018, 05:42 AM

QUOTE(Dave_Darling @ Jul 31 2018, 09:11 PM) *

Again, check all of the wires and hoses to make sure they are plugged in.

--DD


Thanks for the reminder Dave. smile.gif I believe that I do have them all plugged in but lets go step by step and make sure. Here I image one is the back of the Dizzy which should have a plug with three wires
Attached Image

Here are the grounds for the injectors. I was fearful of their connections So I have made them a new ground here.
Attached Image

Here is an image of the intake pipe which has a vacuum line that runs over the piece that connects to the Dizzy.
Attached Image

Then the last picture is to the hand grenade looking thing that attaches to the passenger rear fender wall.

What else should I be checking?
Attached Image

Posted by: mgphoto Aug 1 2018, 09:01 AM

Pump keeps running after the 2 second interval means someone fiddled with the relays on the relay board.

Posted by: LanceW3544 Aug 1 2018, 09:17 AM

QUOTE(mgphoto @ Aug 1 2018, 09:01 AM) *

Pump keeps running after the 2 second interval means someone fiddled with the relays on the relay board.



All three relays are there. Are each of them interchangeable?

Posted by: mgphoto Aug 1 2018, 09:27 AM

QUOTE(LanceW3544 @ Aug 1 2018, 08:17 AM) *

QUOTE(mgphoto @ Aug 1 2018, 09:01 AM) *

Pump keeps running after the 2 second interval means someone fiddled with the relays on the relay board.



All three relays are there. Are each of them interchangeable?

They are interchangeable but they must align correctly, the pins will fit and you may get some function.
The relays will fit in the socket several different ways but only one is correct.

Posted by: Dave_Darling Aug 1 2018, 09:36 AM

QUOTE(LanceW3544 @ Aug 1 2018, 04:42 AM) *

What else should I be checking?


Make sure those are plugged in solidly.

Check the CHT connector. It's near the #3 spark plug; a single wire comes out of the engine tin and goes into a plastic box connector. Sometimes the connection gets broken but the wires still go into the box.

Do you know if the ECU is getting power? You can remove the ECU and check its connector for power on the correct pins. You could also turn the key on and then grab the throttle and open it. If you hear the injectors click (it will be about 10 times), then you know the ECU has power and can send it to the injectors. If you don't hear them click, it's not definite that the ECU isn't getting power, but it shows something isn't allowing the injectors to open at all...

--DD

Posted by: LanceW3544 Aug 2 2018, 03:21 PM

pulled all the relays which I have done before and firmly pushed them all down. For some reason this time something was different. I put about 20 miles on it thus far. Run but bucks a low RPM.

Thank you everyone for your help. You all have been great!


Posted by: Chris914n6 Aug 2 2018, 03:39 PM

Sounds like common corrosion. Give all the connectors a good cleaning.

Posted by: Bartlett 914 Aug 2 2018, 04:28 PM

QUOTE(LanceW3544 @ Aug 2 2018, 04:21 PM) *

pulled all the relays which I have done before and firmly pushed them all down. For some reason this time something was different. I put about 20 miles on it thus far. Run but bucks a low RPM.

Thank you everyone for your help. You all have been great!

Are you talking the round relays on the relay board? Move them around to different positions. This will help rule out bad relays. They can develop bad contacts internally. I have seen small particles of rust that can interfere with the relay coil / armature motion

Posted by: The Cabinetmaker Aug 4 2018, 12:26 PM

One of those relays powers the injection system. The 4 pin connector on the rear drivers side of the board will leave the injection inop if it's not plugged in.

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