Hi Guys, The cars been going okay since i changed the part at the end of the wiring loom in front of the fan, cant remember its name for the life of me. But now its started to misfire again, i'm slowly going up the wall, One thing that i changed on my merc when it misfired was the Air flow sensor, Something i've not thought of changing in the Zed. Anyone got one or can recommend a place, cars a series 1 '90 N/A Auto. Shouldn't have got rid of my spare one...

 

Rich

Sounds like you have an injector out. Got a multimeter? You can check resistance.

 

See video to show you how:

 

[video=youtube;K-2_rO3jGtk]https://www.youtube.com/watch?v=K-2_rO3jGtk

 

cleaned the contacts really well, put it all together and fired her up.

 

 

Any more info and advice gladly received

 

Rich

 

I take it you have cleaned all 6 connectors both male and female?

 

As Si' has said, you need to start eliminating things such as the injectors via the Resistance readings.

My misfire ended up being a pesky plug in the end.

Good little video that.

Good little video that.

 

Agreed..

I take it you have cleaned all 6 connectors both male and female?

 

As Si' has said, you need to start eliminating things such as the injectors via the Resistance readings.

My misfire ended up being a pesky plug in the end.

 

RW are you saying that the misfire in cylinder 3 could be caused by a bad injector connection on one of the other 5 connectors which would show no injector problem on that injector? ... i think..???

 

Rich

Tried to establish whether the line feed to cyl 5 was the issue, with MM tried Stephen's way -ve on earth + on feed in connector, got about 3.9v on MM set on Vac, working on the assumption it fires with a pulsed signal. then i pulled a good cyl and checked that, annoyingly it was the same. Then i remember i bought an injector from someone on here, but before i got it i took one from my spare car. so when i got it i stored it. got the injector and pushed it on cyl 3 connector, i expected it to pulse, it didnt, so i put it on the good connector, still nothing happened. Now i dont know whether it should have done something or shouldn't have , maybe someone can tell me?

 

On the other hand, maybe the line feeds are ok and not only is the injector in the car stuffed, but so is the one i bought?

 

I think i'm going to spend my spare time machining the plenum and replacing the injector, just for the fun of it.

 

keep watching...

Have you not tested the resistance of the suspect injector yet?

Just a quickie. whilst using my Fluke Multi meter, when i set it to resistance should it show "0"

 

Rich

0 resistance means no circuit or broken circuit. It the injector should show 13~14ohms

RW are you saying that the misfire in cylinder 3 could be caused by a bad injector connection on one of the other 5 connectors which would show no injector problem on that injector? ... i think..???

 

Rich

 

Ah, sorry Rich, just read through the post again were you have identified the #3 injector as to be the problematic one.

Mind you, if one connector is that corroded, stands to reason that the other 5 may be as bad.

 

Good luck, hope you fine the issue soon.

If Stephen has to ask you to measure the resistance of that injector one more time... I'm gonna... Measure the blinking resistance! ?

0 resistance means no circuit or broken circuit. It the injector should show 13~14ohms

 

0 ohms does not = a broken circuit. A broken circuit is = to the biggest resistance possible.

Youre right. 0ohms means no resistance but in my experience the multimeters express no connection as 0.

Means 'open' circuit.

Youre right. 0ohms means no resistance but in my experience the multimeters express no connection as 0.

 

Incorrect, 0 ohms is a reading of no resistance in a circuit and its what a good calibrated multimeter should show when its test probes are connected together.

 

When disconnected the display should show no reading at all as its not a circuit. A meter that displays 0 ohms when in an open state is useless.

 

Your confusing an ohms test with a continuity test. Pointless using test equipment unless you know how to use it.

A common mistake, in respect of open and closed circuits. In fairness most people have no idea how to use a multimeter at all.

Typically a multimeter set on ohms will show 0 for a closed circuit with no resistance, a display of 1. (Note the gap, the 1 is on the left.) is an indication of an open circuit, i.e. Infinite resistance, it may also indicate that resistance is higher than the setting you have and you may require a higher decimal.

With the digital multimeter I use these are the readings displayed for closed circuit - 0Ω (left) and open circuit ∞Ω (right):

 

If Stephen has to ask you to measure the resistance of that injector one more time... I'm gonna... Measure the blinking resistance! ?

 

Joely my ohm meter appears to be buggered, it shows anything between 3-16 Mohms, but then so do all the other working ones, so you tell me what i should do other than rip cyl 3 out and put a good one in.

 

i found the wiring harness pin-out chart and when i can i will check the wiring

 

I'm trying to think of ways to tell if the inj is working or not. does any one know what voltage they run at, i could put that V across it to see if the solenoid cycles.

 

Just because i'm not reporting back here doesn't mean i'm not trying stuff, when i can that is , all day today i've been stuck on my bed with my back and busted knee, among other things, but i can still think

 

Rich

If you want to discuss the workings of a MM take it elsewhere, please

If you want to discuss the workings of a MM take it elsewhere, please

 

Agreed the multimeter thing is getting a little off topic but it is relevant to what people are trying to help you achieve. Don't be unpleasant to those offering advice and suggestions because things aren't going your way.

Chris, how old are you

 

Oh and who was the comment "Pointless using test equipment unless you know how to use it. " aimed at

Edited August 26, 20178 yr by Rev1Richie

 

Oh and who was the comment "Pointless using test equipment unless you know how to use it. " aimed at

 

Alic

Chris, how old are you

 

Oh and who was the comment "Pointless using test equipment unless you know how to use it. " aimed at

 

Im 37 mate. My birthday in september if you wanted to get me a present. :biggrin:

Right, letme show you all my MM and if someone can make sense i would appreciate it. switch on and it starts around here, after an hour its up to 19.99. put it on a FI that i am sure is ok and it shows the second image, answers the usual way...

Edited August 27, 20178 yr by Rev1Richie

Connect your test probes together and see if your reading drops to 0 ohms. If the mm is working it should.