Code P0316

CSOSA123456

MEMBER
2003 FORD RANGER
2.3L
4 CYL
2WD
AUTOMATIC
88,400 MILES

Hi all,

Getting a P0316 and no other misfire codes; not even random misfire detected. However, I do feel an intermittent misfire on startup, so I don’t understand why there isn’t a specific cylinder throwing a code.

I’ve replaced the fuel pump, injectors, ignition coil, wires, and spark plugs on the truck. I’ve replaced the spark plugs with Bosch double platinum plugs, which I’ve heard anecdotally the Ranger does not like.

I measured the compression and it reads 205, 205, 210 and 210 (1, 2, 3, 4) on a completely cold engine.

Any suggestions on chasing this evil gremlin? Should I suspect a bad injector(s)? Is there a more specific diagnostic for the ignition system than checking the plugs for spark?

4 Replies

I-SMOGEM

MECHANIC
118 POSTS

Hi CS,

Code 316 sets on engine startup if a miss is detected within the initial 1,000 revolutions (which happens quite quickly), therefore, it's something going on during a cold start situation. By what you have done already, there are a couple of situations still to check out.

Check for any key on, engine off DTCs which could cause the Misfire DTC.

Without another specific cylinder noted, I would be looking at the EGR system. For example, if the pintle on the EGR is stuck where it is slightly open, it will cause startup issues, but not so dramatic of a problem than when it's warmed up.

Another situation is a (slightly) bad head gasket where water is getting into a cylinder - especially when a warm engine is shut off and the pressure pushes a tiny bit of water into a cylinder - that is not noticeable except for startup. It will miss until the water has dissipated. Has it been overheating/overheated?? or have you noticed a loss of water and it's unexplained??

https://www.2carpros.com/articles/head-gasket-blown-test

I can tell this is driving you nuts, and I hope this helps.
Glenn

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Friday, January 1st, 2021 AT 5:29 PM

CSOSA123456

MEMBER
31 POSTS

Hi Glenn,

It has been driving me nuts. I’m waiting on a bluetooth OBD2 reader to be delivered this weekend that will let me see live data, which should help me pinpoint ST and LT FT to see if maybe it’s the injectors.

I had a previous saga with the cab heater where I was getting no heat and it turned out to be that the return line to the degas bottle was badly clogged at the hose that wraps around the engine (was a real bitch to fix that). Replaced the t-connector and the water pump.

All that to say that I went down the rabbit hole of checking to see if it was a leaky head gasket; I stuck a borescope in each cylinder with the engine cold and I couldn’t reliably make out any coolant in the cylinders. Plus I don’t see a puff of white smoke from the tailpipe when starting the car. However, it may be too soon to tell if I’m steadily losing coolant.

Another aside is that I don’t always get a rough start, sometimes it starts just fine. And it also runs perfectly fine once the car is fully warmed up.

You think it could be a bad or failing crank or camshaft position sensor?

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Friday, January 1st, 2021 AT 5:48 PM

CSOSA123456

MEMBER
31 POSTS

Update: now getting P0300, 0303 and 0304 as well. Going back to basics and flipping the plugs from 1 and 2 to 3 and 4 and will report back.

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Saturday, January 2nd, 2021 AT 6:45 AM

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

Sounds good. I would try to service the MAF sensor as well. these guide can help us:

https://www.2carpros.com/articles/mass-air-flow-service

and

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please run down these guides and report back.

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Monday, January 4th, 2021 AT 8:32 AM