Your up in Canoga. I used to live in T.O. As for dealers in that area, I don't know. Sorry I can't be of much help there. I would see what the dealer has for a rating. Each place should have a state ID number. By using that number, it may be possible to look up reports and complaints filed against them.

All you really need is to find a good mechanic at the dealership that you get along with as well as feel comfortable with. Someone you can trust and, someone who's got good references. But, I would only bring it in for electrical diagnostics.

IF your handy and you have a meter, you can actually check that TPS quite easily. Do you have a DMM or DMV / meter?

 

yes i have a meter, but to be honest i'm pretty bad at electrical diag. but now i don't think its the tps. today on the freeway it started the stuttering/lugging from 1400 up to 1900rpm. went to the dealership to ask about the obd3 diag which will cost me $100 to hook up to the machine and they cannot look at it until monday at the best. then upon starting the ram to leave it threw out the cylinder 3 code again. *sigh* when i got home i took off the resonator and airbox to look for the egr valve and i believe i do not have one. so it's kinda back to square one and the possibility of a minor head crack. i did the leak down test about a couple hours from running on a warm day, thought that would show the valve leaking or head gasket.

so any other suggestions would be welcome. thanks and have a happy holiday!

 

Hey, that's a great price. Out in the IE, they are charging twice that amount for a scan. Go for that for sure.

So, your having misfire issues? Does the truck pop through the pipe at all and, do you have a shake as well? Still, don't rule out the TPS yet. Like I said, they can become funky within a certain range. So, from 14-1900 rpm you may have a bad range or, intermittent contact issue inside the TPS where the wiper is not making good contact. So, let's not rule that out yet.

There's a way to test that and, all you have to do is simply backprobe the connector and run it from closed to WOT and note any drop outs in voltage. Do you have a Haynes Manual? They cover this pretty well. You first verify voltage going in (purple / black wire) and then using the other two wires, backprobe the connector and with the key to <ON>, just watch the output on the meter as you slowly open up the throttle. Look for a drop-out or a voltage dip or spike at the output.

But, if your not comfortable, have the dealer run the test. It's the best thing as it will check all of your sensors not just the TPS. They will also look at the sync offset value. They may re-time your cam as well. It could be any of the following:

-bad battery / out of range voltage condition
-bad supply voltage going to the coil which would / could be bad ASD relay @ high contact resistance or, the feed wire has high resistance or, is partially shorted to, the coil is going out.
-bad coil: if the coil is intermittent, the coil may not be able to keep up at certain rpms thus not sending proper voltage to the cap
-bad ECU: you may have a problem with your ignition module or, the coil driver circuit. This is what controls the coil on / off pulses in time with your injectors
-bad / faulty / intermittent dwell circuit at the distributor level.
-bad / worn distributor bushings
-bad / faulty / improperly routed / wrong resistance ignition wires: you may have any of the afore mentioned issues thus causing misfire conditions
-fouled plugs: bad valves, rings etc thus causing intermittent misfires
-bad head: you could have a dry crack: cracked at the spark plug to valve seat or, crack between valve seats to stuck valves etc.
-exhaust manifold leak: thus sucking in cold air through the leak on the intake stroke thus causing it to run lean thus misfire. When both valves are open at the same time, the air is sucked through the exhaust valve up into the intake valve. I had this happen. If the air is cold enough coming across a hot valve, it's enough of a thermal shock to cause it to crack in some cases.
-Intake vac leak: IAC gasket may be dry-rotted and leaking or, it could be a worn throttle shaft in the TB, Plenum gasket leak- it could be any of the lines, brake booster to, a PCV valve to finally, injector O-rings. All those cause it to run lean thus cause a misfire.

-Fuel Pump: low fuel pressure results in misfires. Less pressure means a leaner running engine. Couple that with low compression and you now have a good recipe for misfires. You could also have a faulty fuel relay. Again, high contact resistance thus low power at the pump thus, low power equals slower motor rpms thus less fuel pressure thus a misfire condition. Under certain loading conditions, this can be more noticeable.

-Rusty Fuel Rails: Thus clogs injectors or, at least, restricts fuel flow thus leaning out the mix, thus misfiring.
-Injector issue: high resistance, restricted or clogged thus leaning out mix thus misfiring.

-Sensors:
-CPS, CKPS: these control timing throughout the rpm range. If one is dropping out or showing low output at the ECU input, it affects the timing.

MAP sensor may be intermittent / faulty under certain load conditions.

ECT: this is the primary sensor that feeds the ECU input voltage that corresponds to engine temp. If it's reading erroneous at the ECU input, the A/F mix goes out of whack thus leaning it out too much thus causing misfire.

IAT: this contributes to the ECU tuning the A/F mix as well. Colder it is: supposed to run it richer and, conversely, hotter it gets, it runs it leaner. If the voltage is out at the ECU input, same scenario as with the ECT- too lean and misfires occur.

IAC: it may be opening too wide at certain rpm ranges. Too much air, runs lean, again, misfire.

This is why it's best to just pay the 100 bucks and have the whole thing scanned. It's fun to do all the work but, if you looking to find the root cause ASAP; fastest way to do that is to scan it with a pro tool. You will see everything that the ECU is seeing not just what voltage is present but, actual values in the ECU memory while running and under loading on a dyno as well. They will cycle the vehicle through rpm ranges. Then, later, they play back the test run along with reading any alarms in the software for out or range sensors, firing information, dwell time, primary voltage, timing offset and a whole lot more.

Hope that helps.

 

wow again many thanks!!!

yes i have a chilton's manual and will start working on it later in the week.... one thing thou that i might have just realized. again i bought this truck from an arizona theft auction as is... so no real history, but yesterday while looking for the egr, tps etc i looked at the battery... i don't think it's the correct battery for the truck. it's new but the frame grounding wire does not reach the hole it's supposed to and the body grounding looks like it was not attached at the correct place. it seems the posts should be vice versa for everything to attach up right. then reading your comments gave me a *uh-oh* moment. so, maybe the battery causing all this haywire... letcha know thanks!

 

oh and no popping out the pipe from the misfire's. cylinder 3 plug was dry and sooty/carbon. after 250 miles on new plugs it has some slight tanning. only cyl 3 everyone else is fine. and only stuttering/lugging in overdrive at 1400 - 1900. not any other gear. thx, joe

 

Ok, no popping is better overall. Popping is usually valves. But, if it's just a misfire code, you may want to have them run a comp test to rule out low compression on cyl No 3.

If it's solely No 3, we can narrow it way down. First of all, I would isolate No 3 wire away from any other wire as well as No 7. But, while your rerouting your wires, remove No 3 and measure the resistance of the wire. Use paperclips attached to each probe and gently bend the ends over to round them off. This prevents an accidental hole from being poked in the boot. Slip the clips between the boot and terminal and note reading. Pull the cable taught and note reading / drop out. Bend the cable at the boot end first and note reading. Bend it at the dist end and note reading.

If during any of the tests, the reading drops out, or the resistance shoots way up, the cable is bad. If the cable is good, proceed to rerouting it and then run it. Test it out and note if it misfires or not.

Now, if the results of that simple 101 test fails, then we are looking at a possible injector issue on that cylinder or perhaps something else relating to head and valves / rings / low compression.

First: lets check for a vac leak at the injector o-ring. To do this, simply start the vehicle cold. This test should be done while cold. When it's hot, the intake and injector expands thus closing any gaps. Pop the hood and get a rubber tube ready to go. Start it. Climb up and probe around No 3 at the intake. Listen for hiss / steady wind sound. If it's leaking- there's a problem with the o-ring at No 3. It must be replaced. To do this, bleed the lines down to zero at the Schrader port. Remove the rail bolts, pull the rail up with the injectors attached. This prevents gas from going all over the place.
Place a rag over the intake ports to prevent dropping an o-ring into there. Remove the old o-ring off by rolling it over the end. Take the new o-ring and using a cotton swab or clean fingers, lightly oil the entire thing with mineral oil. Do not use grease or Vaseline. It would be a good idea to replace all the o-rings with new ones. Tops and bottoms while your at it. Rob Stark knows where to get good o-rings. Here's his site: http://www.robstark.com/fuel.htmHe has some from good material. He's a good friend of mine. Those are the only ones I use as all the others that come stock have been hit or miss in both ID and OD and material quality thus being leakers.

NOTE: One thing to remember while doing this is that cleanliness is the main thing to focus on. Using dirty hands to apply oil is bad practice on fuel rings. Debris makes it's way into the injector thus ruining them as well as causing leaks. So, the cleaner and neater you are, the better the outcome in the end.


Next test: Mechanical Injector Test

Get a long prybar or, something that conducts sound well such as an Al rod or Al tubing. Anything you have lying around that will reach each injector to your ear.

I use a 3 foot pry bar with a plastic handle. Plastic handle is a good idea just in case you contact something live such as a plug wire as it acts as an insulator. It's a bit safer than poking around with a crow bar on a live engine. Use something with a nice thin end that comes to a point. You can rest it on the injector body without it slipping better than with a large, dull end.

So, place the bare steel end onto the body of the injector and the insulated handle into your ear. Listen for a consistent ticking sound on No 3 injector. If it is clunking and not consistent, there's your problem. However, if it's ticking in perfect rhythm / timing, well, we would have to pull it out and test it to see if it's clogged or not. It may be receiving power and all but, it may not be passing enough fuel into the chamber to burn.

For safety reasons, I am not going to have you pull the rail and run the engine to see if No 3 is firing. It's unsafe and just plain stupid. There's also a way to do it by applying 12 VDC across the terminals but, if your not careful, you can kill the injector by accident. I recommend having them tested professionally.

If you want to have them tested, Rob Stark can do that for you. Tell him Chris McKenna sent you. He's out here in the Inland Empire and is the only guy in the valley that everyone in So Cal uses including myself.

Now, if it's not an injector, it may be a head or cylinder issue at which point, you had already done a leak down test and a comp test that proved to be fine. Is this correct?

It is also possible that it could be a faulty / intermittent injector driver controller at the ECU or, even a bad harness. I also had that happen. I think I have had almost every possible thing happen at one time or another.

Here's what I want you to check:

After removing the battery negative lead, I want you to carefully remove the No 3 wiring harness at the injector. I then want you to measure the pin contact inside of the injector. Also, if possible, take a reading of the injector resistance while you have the connector off. Set the meter to ohms and measure between the two contacts. OEM resistance reading should be approximately 12 ohms ± 1.2 ohms at 20°C (68°F).

After that checks out, take a pair of calipers and measure the thickness of the contacts. Should be around .035".

Now, using feeler gages, check the gap at the connector. The OEM injectors are usually Siemens and, thickness is ~35 mils. Check the gap inside the connector and note if it's <35 mils or >35 mils. Usually, this ends up throwing an OBD code relating to open injector circuit though. But, those OEM connectors do wear out over time so, check them anyway. They did on mine and were very sloppy and created misfires like mad. See pic. The worn out OEM connector is on the left. Note the huge gap there. THe new one is on the right and, as you can see, the gap is closed. This makes a nice tight fit.

[IMG][/IMG]

Start there and let me know what you find.

 

hey chris,

thanks for all the advice and help... big appreciation on my end.

ok, i did get a correct battery... luckily it was bought by the action house at walmart in oct, so i took it in and exchanged for the correct one.

1. i do not have the typical spark plug wires or boots. it's a distributorless system with the coil plugged in over the plug then connected to the injector and wire harness.

2. upon cold start i could not detect any leak on the injector at #3. however, with the airbox and resonator off there could be a small one.

3. the injector sounds fine at idle and 1400 and 2k. i checked all at idle and #1 and #3 at speed. i left a message with rob to get quotes on checking and cleaning the injectors.

4. the gap at the connector to the injectors is bigger then .035 but it's consistent with all the other ones... the truck only has 28k on it so it looks like i'm the first one to check it out.

5. the resistance at the connector of #1 and #3 injector is 2.5 megohms give or take .03. i had to put paperclips into the connector since my meter leads were too large to fit in with out increasing the gap.

yes i did a leak down and comp test all a-ok.

so...

as i look at it my options, it's gotta be electrical or injector at speed.

that leaves pulling the injectors to check/clean... and i still have to do a fuel pressure test

or pay the $100 for the scan....


again, thanks for all the help.

joe

 

Joe,

something does not sound right in regards to ohm test. 2.5 Mohms is very high. The meter leads are tol be placed inside the injector itself. There's plenty of room so, I think you may have been measuring the harness instead?

When measuring the ohms, measure the injector itself and see if it falls within specs.

I noted that your running a newer RAM and that it doesn't have a dizzy. So, in that case, you'll need to check the ignition module and coil pack if applicable.

Also, that gap must be compared to your injector contacts. That is the key. The difference between the injector blade contact and the harness gap is what you need to measure. All of mine were 35 mils + but, all were over-gapped thus resulting in intermittent contact thus causing misfires.

In your case, you may find it's a bad coil relating to No 3. A bad pump would affect all cylinders not just one. Have you checked the plug torque and plug condition?

I believe that if it's only relating to cylinder No 3, it is most likely isolated to that cylinder only. Coilpack, harness, module, injector, compression, vac leak, spark plug. If the compression was 160 psi, or greater than 100 psi, it is passable thus ruling that out. Or, you may also have a leaky valve that is intermittent. I have this issue and, when testing it in for both compression and leak down, sometimes it passes and sometimes it fails miserably to where I get 60 -90 psi. In my case, there's an issue with the valves and, the engine is going to be torn down tomorrow and new heads are going in.

So, it may or may not be electrical but perhaps mechanical.

Hope you track it down.

Chris

 

hey chris,

yea i'm not too good at electrical... you are correct i was measuring the connectors not the injector. upon re-checking both #1 and #3 are running 11.3 ohms.

i took it out for a 60+ mile drive today and the same is happening... fine in town... on the freeway as soon as it kicks into overdrive btw 1400 and 2k rpm i get the shuttering/lugging. it does not do it any gear except od. then after shutting down and restarting does it throw the #3 misfire code.

yes, the compression is at 180psi in #3 and lower in the others. i have moved all the coils and the code does not follow the coil, it stays at #3 p0303. you are correct that it still could be an intermittent mechanical failure, but my gut is telling me electrical since it only happens when it kicks down in od.

i think i'm going to make an appt for the scan at the dealership... and i hope it only a re-programming issue.

once again i cannot express how much i appreciate the help!!! if we ever meet up a 6 pack is on me for sure.

happy new year, joe

 

wow thats a lot of info.heres my .02.OBD 3 isnt out yet.Current system is obd 2.IAC doesnt open except at idle.Wont cause an engine to go lean.A good pocket scanner will cost about 200 bucks.You can read data and freeze frame it.And it will save future dealer trips,plus its a tool,and those are cool.If it were mine I would ohm the wires to #3 cylinder and fix the break in the wire.If thats not it maybe an injector is acting up{swap em around} but I think its a wire rubbing somewhere.Simple repair.No sense in doing brain surgery for a headache.