Cylinder one compression check

Tiny
HIDDEN1
  • MEMBER
  • 2001 DODGE DAKOTA
  • 3.9L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 190,000 MILES
I might need to check the compression on Cylinder one.
What range does it need to be and is it best to pull all the plugs or just that one?

Also, I'm not sure if this may have damaged anything but when I was turning the crank manually watching distributor and had a dowel in first piston watching it as it goes down and then up at compression stroke and putting it to TDC dowel got stuck. I rotated the crank backwards a tad and was able to get it out but there was a bent in it about an inch from the top. (See picture below) I'm hoping no problems or rings impacted. What should I look at doing before I start up? And cylinder compression test.
Pic is of dowel next to another one after I got it out.
Do you
have the same problem?
Yes
No
Friday, April 22nd, 2022 AT 7:14 PM

31 Replies

Tiny
STEVE W.
  • EXPERT
What is the reason for the compression test? Misfire?

You will want to remove all the plugs and hold the throttle wide open while testing. Pull the fuel pump fuse as well. As for the reading, with 190,000 on the engine I would expect to see around 130 - 140 PSI. 100 PSI is the minimum for that engine and a really good one would show 160 or a bit more. You don't want more than a 10% difference between the highest and lowest cylinders. So, say you tested and all six read between 130 and 140. That's good If you test them all and get a high of 150 and a low of 100 that would be bad. Check out this guide to show you how:

https://www.2carpros.com/articles/how-to-test-engine-compression

Please let us know what you find.
Was this
answer
helpful?
Yes
No
Friday, April 22nd, 2022 AT 8:01 PM
Tiny
HIDDEN1
  • MEMBER
I was curious if ever I needed to check it.
How can I tell if my engine is seized?
I can still turn crank manually (reinstalled starter after testing it). The starter that was put back in after changing oil pan gasket I first bumped it a few times, then tried to turn over engine and nothing but a "vroom" noise, is that the Bendix not engaging? Fuse and relay okay.
I turned crank again manually, a bit tough but not anymore than before when I put balancer on.
Is it seized?

Where do I start?

Pull starter and get retested?
Look at flywheel?
Any info is appreciated.

.
Was this
answer
helpful?
Yes
No
Saturday, April 23rd, 2022 AT 8:58 PM
Tiny
STEVE W.
  • EXPERT
If you can turn the engine over two full turns using a ratchet on the crank pulley nut it's not seized. Sounds like the Bendix isn't engaging. Could be a bad starter or not attached fully.
Was this
answer
helpful?
Yes
No
Saturday, April 23rd, 2022 AT 10:00 PM
Tiny
HIDDEN1
  • MEMBER
Yes, Bendix is what I'm hoping. I'm going to take it off and go take in to get tested but do those bench testers tell you if Bendix is engaging?
Any tips or what to look at as I reinstall next starter. I'm not sure I want to reuse that one.
Was this
answer
helpful?
Yes
No
Saturday, April 23rd, 2022 AT 10:06 PM
Tiny
STEVE W.
  • EXPERT
If the Bendix kicks out when the solenoid engages it will show on the tester.
Was this
answer
helpful?
Yes
No
Saturday, April 23rd, 2022 AT 10:10 PM
Tiny
HIDDEN1
  • MEMBER
I will also test what the voltage is on battery to know if maybe that factored it, but it seemed strong. I will recharge the battery too. I don't think that's a factor since it ran fine a few days ago after timing chain but all it takes is a slight drop in volts not to start.
Thanks for the support!
Was this
answer
helpful?
Yes
No
Saturday, April 23rd, 2022 AT 10:14 PM
Tiny
HIDDEN1
  • MEMBER
Tested the starter and it was great. Bendix engaged. I got another one then tested it and all good, but I'll put that other one I just got in it.

Should I look at anything or flywheel or specifically try as I put starter in? And do these ever need shimming?
And what's the ft lb on starter?
Was this
answer
helpful?
Yes
No
Sunday, April 24th, 2022 AT 1:07 PM
Tiny
STEVE W.
  • EXPERT
50 ft lb tightening on the mounting bolts. No shims. Check the flywheel ring gear for damage or missing teeth.
Was this
answer
helpful?
Yes
No
Sunday, April 24th, 2022 AT 3:22 PM
Tiny
HIDDEN1
  • MEMBER
Got it on, it engaged better. Turned over and started, then after starting up an odd low pitch sound from engine. So, I turned it off.
What do I need to check next?
Was this
answer
helpful?
Yes
No
Sunday, April 24th, 2022 AT 7:16 PM
Tiny
STEVE W.
  • EXPERT
Without hearing it I have no idea if you have a problem. What was the first issue you had that made you work on it? You asked about compression first, what was the reason for that? It didn't run or was running bad?
Was this
answer
helpful?
Yes
No
Sunday, April 24th, 2022 AT 11:09 PM
Tiny
HIDDEN1
  • MEMBER
I had a leak at the timing chain cover and went ahead and changed the chain, and correctly got the dots lined up. I had to reinstall the balancer to 130ftlbs, until I could get the tool to torque it higher -180. It started up and ran fine. I got a bigger torque wrench and the balancer install tool also and tightened it in more. Then tried to get torque on crank bolt over the 130 but, balancer turned on me some even with bolts in and long bar against frame. I used a quick impact gun from there. I turned the balancer clockwise a few turns back to the TDC mark.

At earlier first start up, after timing cover an all were back on and 135ftlb on balancer, oil was dripping at torn pan gasket. That oil pan gasket got torn where the timing chain cover is at.

I had to jack up the motor, take off the motor supports and raise it more, pull the starter, take off the transmission supports, and overdrive supports to raise it more, and get into my oil pan better, and get the piece of pan gasket that was in bottom. (This pan can't fully come out without pulling engine) New oil pan gasket installed. I noticed the starter reinstall was a bit tight, but it fit in okay.

I bumped the motor a few times, then that vroom noise, like started didn't engage.

Pulled starter it tested okay, but i, put another in that tested good.
I recharged the battery and turned it over.
This time the starter had the normal turnover sound, then the engaged sound but once it engaged it didn't sound like a normal run-on engine low pitch noise and not that regular running sound. I didn't just let it continue, and I quickly turned it off.

A little while ago I slightly turned the starter over with the key, it had the normal turnover sound, and turned it off, and then looked at balancer and it is turning.
Was this
answer
helpful?
Yes
No
Monday, April 25th, 2022 AT 7:33 AM
Tiny
STEVE W.
  • EXPERT
Record a video of it running and post it, from the description I'm thinking you have an exhaust leak from jacking the engine up a ways, but without hearing it?
Was this
answer
helpful?
Yes
No
Monday, April 25th, 2022 AT 1:41 PM
Tiny
HIDDEN1
  • MEMBER
I pulled the starter and cover plate to see the teeth in flywheel. Even turned engine by crank to see entire wheel and didn't see any teeth out. Here is the pics.
No, it wasn't in run mode at all. Once an odd noise hit I shut it off to look at the flywheel.
When pinion engages it can't bind can it? Since both turned?
Was this
answer
helpful?
Yes
No
Monday, April 25th, 2022 AT 4:14 PM
Tiny
HIDDEN1
  • MEMBER
Update: After the pics it started up fast and smooth this time. I turned it off after a few seconds for the time.
I had taken off that aluminum guard piece covering the flywheel. And temporarily put starter back in and tight.
Turned flywheel /at crank back to TDC. - It started better than yesterday's second attempt. And far better than the old starter with vroom noise, the engine didn't engage.
Maybe that bell housing, aluminum cover plate is working like a shim to the starter? An after I repositioned things, it started better with it off.
I'm glad I did examine the flywheel after the many different noises.

Does it look okay?

I will be testing the truck, looking for any leaks an letting it run tomorrow as it is.
Can get video. .
Was this
answer
helpful?
Yes
No
Monday, April 25th, 2022 AT 8:04 PM
Tiny
HIDDEN1
  • MEMBER
This was causing all that recent noise. I even cut side off at the starter, still did it. I took it back off, quiet again.
I guess I'll have to get one off another Dakota..I don't really want any debris to get up in there.
Was this
answer
helpful?
Yes
No
Tuesday, April 26th, 2022 AT 12:15 PM
Tiny
STEVE W.
  • EXPERT
Likely it was rubbing on the flex plate.
Was this
answer
helpful?
Yes
No
Tuesday, April 26th, 2022 AT 5:50 PM
Tiny
HIDDEN1
  • MEMBER
Yes, it looks very close to those bolts.

If the next one does the same thing what should I try? Spacers a nut or flat washers at the tranny support bolts an 2 tiny ones, to move it back?

The huge bolts that hold the tranny supports go over the main holes.
Im not gonna wrestel with area under starter ill cut that out.
There are top tabs that tuck in.
Whats the torque on tge huge tranny support bots at the bell housing?
Was this
answer
helpful?
Yes
No
Wednesday, April 27th, 2022 AT 7:57 AM
Tiny
HIDDEN1
  • MEMBER
No go on another piece. It scrapped too. Looks like inside at top of the curve..I noticed theres a bigger gap between oil pan an the bell housing on the other dakota.
Maybe thats a factor.
I had to cut a piece of aluminum off a roll of coil an fabricated one as best I could. But not sure it can prevent all rock or debris from getting in.
I tried to even cut that middle out at curve but still rubbing.
For now that is better than nothing
Any ideas?
I will likely reform another one later. Unless you have a solution.
2nd pic piece is replacement even after middle was cut out -scrape.
Was this
answer
helpful?
Yes
No
Wednesday, April 27th, 2022 AT 3:16 PM
Tiny
STEVE W.
  • EXPERT
The cover should go between the transmission and the block, the thin plate provides the correct clearance for the other parts.
Was the transmission removed before this all occurred?
Was this
answer
helpful?
Yes
No
Wednesday, April 27th, 2022 AT 3:50 PM
Tiny
HIDDEN1
  • MEMBER
No but the engine and transmission at bell house an overdrive had to be lifted or jacked up so as to drop oil pan low enough to get inside it. There's a cross member under oil pan and it's tight. Motor is back on the motor mounts an overdrive back on its supports all tightened back.
Was this
answer
helpful?
Yes
No
Wednesday, April 27th, 2022 AT 3:55 PM

Please login or register to post a reply.

Sponsored links