Exactly What Compression Tester Are You All Using?

[turbocruiser]

Hi all, first I want to write that I had some reservations about making this standalone thread as there were three or so search-provided posts that mentioned compression testers in other threads. Maybe I missed it but those threads basically mentioned brands of testers and did not mention specific models of testers and this is where my problem is as my sears craftsman tester (many moons old) would not work well with my rig due to the depth that the tester much reach to reach the spark plug hole; the gauge would literally stretch to sit right above the valve cover if at all. So I was wondering what specific model of tester works well with the 80's configuration??? Two or three people mentioned sears already and I was wondering whether the following tester is the specific tester you are using (as I wrote already, my "sears" tester wont work.) Thanks again fellas.

http://www.sears.com/sr/javasr/product.do?BV_UseBVCookie=Yes&vertical=TOOL&pid=00947089000

 

[turbocruiser]

Bump.

 

[Rookie2]

Seems like the one picture I've seen on here was a standard tester (pressure gauge with about a 1 foot long rubber hose, and threaded end), with a homemade rigid extension for getting down in the tubes. I also posted a similar question about availability of testers that would work well with the valve cover tubes, but don't recall getting a response.

 

[brent]

I just got a tester about two weeks ago at Sears and it looks just like that kit, mine did come with an extension though so that the gage has its own flexible foot long hose with fitting which attaches to the other foot long piece that connects up to your spark plug hole...........think it wa about 50 bucks, I would think it would be pretty easy to make an extension???

 

[whodat]

got mine at Harbor Freight for $20. I think everything they sell is $20

 

[turbocruiser]

Seems like the one picture I've seen on here was a standard tester (pressure gauge with about a 1 foot long rubber hose, and threaded end), with a homemade rigid extension for getting down in the tubes. I also posted a similar question about availability of testers that would work well with the valve cover tubes, but don't recall getting a response.

Yes, I remember that picture and I sorta remember that the picture did not show any symbol or brand or model??? At least I hope that's right? Whoever posted that pic would you remind me what make and model that tester was and if it came that way or if you adapted it?

I just got a tester about two weeks ago at Sears and it looks just like that kit, mine did come with an extension though so that the gage has its own flexible foot long hose with fitting which attaches to the other foot long piece that connects up to your spark plug hole...........think it wa about 50 bucks, I would think it would be pretty easy to make an extension???

Brent, super cool start, would you mind sharing what specific model number your tester is? It should be listed somewhere on the tool or the tool packaging that it came in. Or am I misreading and you got the same sears tester linked above but it included the longer extensions? I'm sorta reading that wrong I think but it sounds like sears changed the innards of the kit but they retained the same model number? That might make it even harder to track down, crap!

got mine at Harbor Freight for $20. I think everything they sell is $20

Yea, no kiddin, some killer deals droppin over at the HF. Once got a lifetime warranty extra large standard socket impact set for 20$. Was hoping they would come out with the same thing in Metric but so far, no go. Anyway, Whodat, the same question as the one I asked Brent, would you mind sharing what model your tester is?

Like I wrote in the first post, I sorta assumed that my trusty rusty sears tester would work but it wont so before I go through the trouble of tracking down something that would work (back and forth to the stores with six holes open sittin in the garage, arrrggghhh what agrivation!), I thought I should just ask you folks. Thanks again.

 

[turbocruiser]

Last bump I promise. I really wanna figure this thing out.

 

[brent]

turbo

I was working on the rig last night but will checl tonigh to see if the model number is different from the one you had, it looked almost exactly the same, will check though, might even be able to take a pic............

 

[Rookie2]

IIRC, concretejungle posted the pic. with the tester and the homemade extension. I believe he indicated that he borrowed it, so may not remember what the model was. It was pretty resent. Did you try and search it?


Rookie2

EDIT: Here it is. https://forum.ih8mud.com/showthread.php?t=39951&highlight=compression.

Too small to see what brand.

 

[Gumby]

I use a Snap-On tester I have had for about 15 years. It uses different 8-10" hoses with different threads that have a air-hose type connector to a foot long hose attached to the guage. The schreader valves come out of the hoses so they can be used for leak down testing.

 

[turbocruiser]

turbo

I was working on the rig last night but will checl tonigh to see if the model number is different from the one you had, it looked almost exactly the same, will check though, might even be able to take a pic............

Thanks Brent, that would be awesome, I appreciate it!

IIRC, concretejungle posted the pic. with the tester and the homemade extension. I believe he indicated that he borrowed it, so may not remember what the model was. It was pretty resent. Did you try and search it?


Rookie2

Too small to see what brand.

Thanks R2, yea awhile ago i searched and saw that thread and that pic but could not see the brand and the other thing was that i could not tell what part of the gauge was stock and what part of it was modified. Thanks for posting that link though.

I use a Snap-On tester I have had for about 15 years. It uses different 8-10" hoses with different threads that have a air-hose type connector to a foot long hose attached to the guage. The schreader valves come out of the hoses so they can be used for leak down testing.

G, thanks man, I appreciate it, with the amount of use you probably put on your tester, if it lasts 15 years, its gotta be good! The description you provided alone is adequate to match the tester to something in their inventory and I have a heckuva cool snap on rep that rolls through my area at work and always welcomes me to "hop on" and look through the rolling toy store. He was the one that got the tool that Junk recommended for removing hoses. Thanks again.

I really appreciate all the awesome assistance fellas.

Signed: "Stalking the SnapOn truck!" aka TurboCruiser

 

[brent]

My model # is 47089, will to get th pic going here

 

[turbocruiser]

My model # is 47089, will to get th pic going here

Right on Brent! Thanks so much! I really appreciate it!

 

[turbocruiser]

Some Additional Questions

Hi all, well I went and picked up the compression tester from sears that brent and some others recommended. Thanks again fellas for the recommendations. The kit looks like good gear; nice hoses, lots of adaptors, nice gauge. Of course the kit is no where near as nice as the Snap On ones I'm sure, but, I'm a weekend warrior and not a pro like Robbie, Gumby and some of the others here so I figured 50 bucks vs. 225 bucks was better at least for me.

I hope to test the compression this weekend when i'm scheduled to swap the plugs and in preparation for that i read the instructions to the tester. One thing in particular was perplexing ... there was a long warning written about NOT using the ignition switch on fuel injected vehicles and that a remote start switch should always be used with any fuel injected vehicle. The explanation was that some but not all late model vehicles trigger the fuel injectors when the ignition switch starts to crank the engine. The warning was worded in a way that made me think this feature cannot be cancelled in these vehicles although I think in essence many here have found a way to do that to their rigs. Is this why some here recommend removing the efi fuse or the efi relay? What really is the right way to disable the fuel injectors cause I'm sure almost everyone IS using the ignition switch, right? There was a thread that pretty clearly spelled it out but when i just searched for some reason i could not find that thread???

The other question, and something that I think was also answered in that other thread was, what is really the right way to disconnect the coil? Should you simply remove the lead from coil to distributor? Should you remove the small two wire connector that goes to the coil and then just let that hang at a distance? Should you do both? I seem to remember something about one way that works but potentially stresses the coil pretty hard, I'd like to avoid that way.

The last question, I promise, is several here suggested that by the time that you get to the last cylinder alot of times the battery is worn down somewhat from all the cranking. Would hooking up a trickle charger while testing the compression by advisable? Or, would hooking it up in the middle of the test and letting it charge while enjoying a #6 be part of this procedure? I cant imagine the batt getting that low that fast but if I should charge it in the middle or throughout the test, then that is easily done as well.

I'd appreciate any advice at all about any of this. I know much of it was covered but again I cannot seem to come up with it, and at least in my memory there was some conflicting opinion, imagine that! Thanks again all, and thanks especially to brent for traking down that part number for me.

 

[turbocruiser]

Wow, this is really wierd; I have been searching and searching for the thread that recently specifically answered several of the questions I was asking above. I typed in "compression" , "compression test", "compression gauge", "how to test compression" and several other variations that i thought would reveal this terrific thread I remembered. Well, nothing worked and I was getting frustrated and ready to bump this thread to the top in the hopes someone would remember the same things I thought I remembered! Then while reading this exact thread again I see the link that Rookie2 referred to in post # 9 and sure as snot, that's the friggin thread I've been looking for all along. I went and retried it in search and it is still not showing in search! What the heck am I doing wrong? Is it possible that once a thread is linked into another thread it then gets hidden from search? I would not think so, so again, what the heck am I doing wrong? Anyway, I found the answers to the questions I asked, so I'll answer them here for myself and anyone who would want.

General rule of thumb for a compression test:

Remove all plugs and disconnect power to coil

Hold throttle wide open

Turn key and count 10 cycles. RUR RUR RUR... you get the idea.

Repeat for each cylinder

Here's how i did it:

1. Remove all plugs (might as well remove the intake since it's right over the top of #3 and #4).

2. Remove the EFI fuse.

3. Put compression tester in cyclinder, and place the dial on top of the motor so i could see it under the hood from inside the truck.

4. Crank on motor, with gas pedal pressed 100% watching dial until it reaches the highest pressure and will not climb any higher (this was an average of about 4 to 6 seconds of cranking).

5. that's it, continue this for each cylinder.


Ron, i don't think it's necessary to ground the coil, just be sure the ends of the plug wires are not touching any metal or anything (i just let mine hang to the side).

This is very easy, i was surprised after i did it just how simple it was.

You can pull the EFI relay in the box just as easy as a fuse.

Grounding the coil wire can have adverse results, an open is better than a ground. Unplugging the coil from the vehicle harness essentially leaves an open.

On mulit-point fuel injected cars fuel is sprayed at a fairly high velocity into the intake manifold just upstream of the valve. When you remove all the plugs the fuel now has an exit and will create vapor in and around the engine compartment. Should any of the spark plug wires decide to throw a spark in the right place at the right time you may experience a slight flash of fire. It's surprising let me tell you. I've seen it happen on a Subaru XT. (No I didn't do it)

It is a good thing to also disconnect the coil, for no spark and no damage to the inginitor circuit. If you pull the EFI fuze then no fuel gets sprayed into the cylinders to mess with. I use the 10 cycles also. By using 10 cycles you remain consistant. Even new compression testers can be off by a few % points. 175 new is the book value. a few over could mean carbon build up, or the testor is off a little. But having them consistant is a great thing. later robbie

So, those answers are what i was remembering enough to remember being there but forgetting enough to forget what the take home message was! what a dumbass i am. Anyway, I think I'm clear on all of this except for two specific confusions: first, i dont understand what you were saying sixs about spraying fuel around above the valve cover ... if either the EFI fuse or the EFI relay were pulled out, how could the injectors still spray the fuel that clouded up over the engine? What am I missing there? And secondly, I cant tell from what was written exactly what the preferred way is to "disconnect the coil" ... do you unplug the two wire connector, or, do you unplug the main lead from the coil to the distributor, or, do you do both???

Thanks again all, I really appreciate it and hope to do this when I replace my plugs this weekend. If anyone can clarify that last little part, I'd appreciate it. Thanks.

 

[RavenTai]

I think what six is saying is there is a fire hazard if you do not disable the EFI and you will get fuel vapor out of the open spark plug holes, also un-burnt fuel will wash oil of the cylinder walls and load up in the exhaust, if you disable it then no problem. I last had my compression checked at a Toyota dealer during a pre-purchase inspection, he pulled 2 fuses can’t remember witch but the goal was disabling the EFI

For the ignition coil I would pull the 12v plug (2 wire) if you pull the high voltage wire leading to the distributor the coil will still fire and jump up to several inches to the closest ground, if you are nearby it will use you to ease its path (flesh is more conductive than air) , ignition current is generally non lethal because the amperage is very low but dam it hurts.

The official word on checking the compression

www.raventai.com/PDF/insp.pdf

Note that it calls for removing the plug from the distributor, the standard low voltage plug not the spark plug wires, spark plug wires are called “high–tension cords“ in the FSM, I guess this has a similar effect, without a signal from the hall effect sensor in the distributor the coil will never be told to fire.

They also call for a fully charged battery so charging between cranks sounds like a good idea, wonder if the PO installed weak battery and cool engine had anything to do with my less than perfect results during the pre purchase?

I have a Mac tools compression tester that I have not tried yet, has a fairly long hose and should work. Have new plugs cap and rotor on the way from Dan, plan to check the compression at that time as a before to compare to after an AutoRx treatment. Some on BITOG have gotten better compression afterwards, the thinking being that carbon in the ring groves prevents them from making a good seal.

 

[turbocruiser]

Wow, thanks RT, great response, makes perfect sense. I hope to post some numbers soon. Thanks again all, this was cool. Still dont know what I was doing wrong with search though! Hmmm.

 

[Rookie2]

TC: FWIW, back when I was trying to track down that thread, I did the same search you described with no luck. Adding concretejungle's username to the search criteria was what ended up getting me there. I was a little puzzled by it all too.


Rookie2

 

[turbocruiser]

TC: FWIW, back when I was trying to track down that thread, I did the same search you described with no luck. Adding concretejungle's username to the search criteria was what ended up getting me there. I was a little puzzled by it all too.


Rookie2

Phew, glad to know that ... I was anticipating Junk slaps when i was working with this thread! So, Woody, or anyone else more computer savvy, can you think through why this would occur? Is it possible that once a thread is linked into another thread it then is hidden from search? Anyways, I'll prolly do the test tonight or tomorrow and I'll post some results. Thanks again for the help all, and R2, thanks for verifying that the trouble with search was not something I was entering wrong! Phew, again!

 

[RavenTai]

something is definatly up

this thread cannot be found by searching for RotellaT nor sludge nor AutoRx all three are in that thread one even in the title, I found the thread only becuse I have linked it on another forum

https://forum.ih8mud.com/showthread.php?t=37922

linking to a thread should have no effect, last tiem this happend somethign was said about database couruption, and re-indexing