Question about Cars & Trucks

1 Answer

1993 gm 3800 left bank disconnecting of plug wire and injection connector does not change idle, appears left bank is not working.. Compression good...

Noid test is good... havnt checked fuel pressure

Posted by on


1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.


    An expert who has achieved Level 3.

  • Cars & Trucks Master
  • 378 Answers

Did you test for spark? I would check spark and fuel pressure. OK, here's a little bit of working theory that'll help you to see the ‘why’ of the Noid light test.

Whether you're testing a No Start Condition or a Misfire Condition, you'll need to know if the cause of the problem is a lack of fuel. When your GM 3.8L (Buick, Chevrolet, Oldsmobile, Pontiac) does not start, it will be either because of a lack of fuel or spark. The same thing goes for when your GM 3.8L equipped car or mini-van is misfiring... that specific engine cylinder isn't contributing to engine power because it either lacks fuel or spark.

Now, since the above two conditions (No Start and Misfire) can be caused by any number of things... one of the things that has to be eliminated, from this list of possibles, is the fuel injector not getting power or the injector pulse signal (On/Off switching signal) from the vehicle's Computer.

This is where the fuel injector Noid light test comes in handy, because you're able to visually see if both of these signals are present or not. If no flashes, then now you know that you have to verify that the connector is getting power (12 Volts) and the injector pulse signal.

One thing to keep in mind, is that the fuel injector Noid light test does not test for a BAD fuel injector. But, is the first step in verifying if the fuel injector is BAD or not. For the fuel injector test tutorial.

Posted on May 07, 2017


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Nissan v6 patrol 1993 engine missfire on l/h bank first cylinder all plugs leads dist cap rotor all been changed still misfire

petrol misfire on left bank only
strange with all the parts replaced
if all spark sorted
plug lead in right order to plugs on left bank

its injected V6 .... it runs getting fuel

might be ecu pulse missing on one injector

is the coil arching or have a crack in it

i would check
02 sensor looks like that motor only has one
vacuum leak s
leaky valves , poor compression ,
or fuel pump .....rail pressure regulator ?

02 sensor ... looks like that motor only has one



Oct 31, 2016 | Nissan Cars & Trucks

1 Answer

Hi I have a 2004 mustang gt and we change the fuel pump and fuel filter and then we check the injectors with a tester and bank 1234 on the passenger side is out and 5678 on the left side is on and ain't no...

Sounds like the power splice to bank one is lost. By injection tester, do you mean a noid light?

Do you understand how the fuel injection circuit works? When the ignition key is in the on position, all of the injectors will have constant battery voltage applied to them. Bank 2 (#'s 5,6,7,8) is good- they are all pulsing. The same power wire is spliced to all 8 injectors. The other wire at each injector is the ground wire, and each ground wire goes separately into the engine computer to be internally grounded for a split second. That is the pulse of the injector, and is when it sprays fuel into the cylinder.

So think about it. Your 5,6,7,8 is working right, but 1,2,3,4 are not pulsing. Not likely 1234, all 4 separate ground wires, just went bad like that. More likely that 1234 not getting voltage to them through that common hot wire. You can check it real fast: check for voltage on any injector connector on bank 1, with the key in ON. The inj. connector only has two wires, a power and a ground wire. One of them should be hot in on. If no power on bank 1 injectors, trace it back to the engine harness. Somewhere, the power wire will splice off between bank 1 and bank 2.

Nov 04, 2014 | Cars & Trucks

1 Answer

01 a6, cyl 1 2 3 show misfire on obd2 scan above idle,plugs wires coil injectors fuelfilter o2sensors allgood

What is the code you are getting? Have you checked the engines compression and all cylinders are in good shape? Do that test and get back to me.

Jun 16, 2012 | 2001 Audi A6

1 Answer

I just bought a pontiac the seller told me i needed some spark plugs and wirers the car cuts off while idleing and back fires. how would i begin to change the spark plugs and wires

passenger side is the even bank
drivers side is odd bank
low cylinder numbers are closest to radiator, highest toward firewall

Use wire pliers so you do not tear the boots or rip the connector ends off the wires.
Get a 5/8 offset distributor wrench.
A "stubby" spark plug socket

Make sure it is clean,

make sure to let it cool completely
Put a box in front of car, draw a fan on it and stab 4 holes on each side of fan with a pen. Do one plug at a time. When you take it out, put it in corresponding hole on box for that cylinder number. This will help you know what clyinders have carbon build up, camshaft condition, compression, ect... by the looks of the plugs.

Dec 23, 2010 | 1996 Pontiac Grand Am

1 Answer

My 1993 jeep grand cherokee laredo idles rough after warm up. it also idels high around 2000 rpm at start up sometimes and needs to be shut off and restarted to calm idle speed. whats is causing the...

usually rough Idle is not noticable at high ildle. Once it is idles normally try Disconnecting one injector at a time. If the idle stays the same than that cylinder is the culprit. Remove that spark. If it is wet than do a compression test. Should read better than 100lbs of compression.If compression is good take a spark plug and hook it into the end of the plug wire.Lay it across the intake,start the car and watch for spark. If you have spark than you probably have a bad injector. A miss will cause the vehicle to idle high. The computer is trying to keep the car from dieing out. Hope this helps. No spark do a tune up.

Dec 05, 2010 | 1993 Jeep Grand Cherokee

1 Answer

1993 acura lengend i change the timing belt reset the timing and now the car wont start, it is getting compression and fuel but no spark the coil, fuses are good all wires are conected but still no spark....

There are six coils on the Acura and they are governed by the ECU. The crank position sensor feeds the signal to the computer and is located under the Camshaft pulley on the left (or front) bank of cylinders. You have disconnected it to get the pulley off and may have jammed the small male probes of the connector while putting it back on. You can re-align them and try again. The sensor also may have been damaged and is not "reading" and giving the ECU information to sequence the injectors. It should show on your engine fault code (OBD2 scan). Take out the ALT/Sense fuse to re-boot the computer codes and check. The 93 coupe has variable valve timing and lift control (VTEC) and the ECU controls intake and fuel pressure.

Oct 20, 2010 | 1993 Acura Legend

1 Answer

Gnitio2001 3.8 v6 new plugs,new wires,and new ignition coil still will not run smooth.also the left bank is not heating up.obd2 said it was number 4 wire ?

Could have one or more bad injectors, another electrical problem, or even a compression problem. Just because it indicates a #4 misfire it doesnt necessarly mean its a wire, could be fuel injection or compression as well

Apr 11, 2010 | 2001 Ford Mustang

1 Answer

Engine miss firing

change plugs and wires distributor cap and rotor.+coil.if all is good .do a compression test.

Feb 02, 2009 | 1988 Chevrolet K1500

1 Answer

Low compression cyl has 20 lbs of compression.

A leakdown test is where you remove the spark plug from the problematic cylinder,and install an adapter and air hose,shop air,about 90 to 120 psi.You have to be certain both valves are closed on that cylinder,and i do this by removing the valve cover on that bank,rotate the crankshaft and watch the rocker arms work on that cylinder,and watch them close completely.Now,install the shop air,and listen for air hissing in the tailpipe,this checks the exhaust valve,and then the intake manifold,this checks the intake valve.Now,you can also listen in the crankcase,and if you hear hissing in the crankcase,then you have bad rings,or a piston with a hole in it.

Sep 23, 2008 | 1993 Chevrolet S-10

Not finding what you are looking for?
Cars & Trucks Logo

Related Topics:

26 people viewed this question

Ask a Question

Usually answered in minutes!

Top Cars & Trucks Experts


Level 3 Expert

79865 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22326 Answers

john h

Level 3 Expert

14512 Answers

Are you a Car and Truck Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides