Questions tagged [testing]

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16 votes
6 answers
5k views

Finding a possible vacuum leak

One of our cars has a bit of a rough idle which disappears at about 1,000 RPM. After eliminating everything else I concluded that this is due to a minor vacuum leak. This was confirmed by the use of a ...
John Gardeniers's user avatar
7 votes
3 answers
21k views

Emissions - High CO reading only

My 1999 Honda CRV has just failed it's UK MOT test on emissions. Results are below: 1st test: CO 0.73 (FAIL - max is 0.30) HC 78 (PASS - max is 200) Lambda 1.008 (PASS - between 0.970 & ...
GoldieLocks's user avatar
6 votes
4 answers
6k views

How do I know when to replace shock absorbers?

In my last trip to the shop, the mechanics told me that I should replace my shock absorbers. When I inquired as to why, I don't feel that they were very clear with their answer, like they normally ...
tarheel's user avatar
  • 885
7 votes
1 answer
4k views

How to test the function of a water pump?

Is it possible to test a water pump for proper function (ability to move a certain volume of coolant) without disconnecting it from the engine? If so, how would one do that?
cdunn's user avatar
  • 9,296
8 votes
3 answers
27k views

Hand-testing Shock Absorbers

Does manually hand-testing shock absorbers have any validity for checking if a shock is good or bad? Does hand-priming shock absorbers help? I usually hand-prime shock absorbers that I feel are ...
agent provocateur's user avatar
8 votes
1 answer
12k views

Cylinder Leak-down vs Compression Test

I understand that both cylinder leak down and compression tests are used to test for cylinder head, cracks, warps, and gasket leaks. I understand the difference between how each works: compression ...
amphibient's user avatar
  • 6,653
6 votes
1 answer
32k views

What is surface charge and how does it affect battery testing?

I've read in numerous places that "surface charge" can give false positives when testing a battery, and you need to remove the said surface charge to get an accurate result. I've also read various ...
Robert S. Barnes's user avatar
5 votes
2 answers
3k views

Block Test: Can't suck any more air, is this normal? (1999 Suburban)

I performed a block test recently to diagnose a problem I'm having. The liquid stayed blue, but I want to clarify I have done this right. The purpose of the test was to see if I could prove a head ...
musicwithoutpaper's user avatar
4 votes
1 answer
11k views

How Many Times to Crank During a Compression Test

I've read a number of different recommendations on how many times to cranks the engine during a compression test. I've read those that say to crank until you reach a stable reading. In the book, ...
Robert S. Barnes's user avatar
4 votes
1 answer
259 views

What Is The Output Voltage For The Mazda 626 GF 2L 98-2002 Coil Pack?

I've seen aftermarket "high voltage" coils that output 40kV, but what is the output voltage for the standard OEM coil pack? I want to use a spark tester with an adjustable gap to check the strength ...
Robert S. Barnes's user avatar
2 votes
1 answer
174 views

How Long to Power the Injectors for a Fuel Pump Volume Test?

I want to do a fuel pump volume test on my 98 Mazda 62 2L GF, but the WSM doesn't say how long to energize the injectors: I'll probably activate the injector by back probing the injector ground wire ...
Robert S. Barnes's user avatar
0 votes
1 answer
456 views

Upstream O2 sensor stays at 0.4V

To test the upstream O2 sensor on a 2011 Toyota Corolla, I backprobed it with a multimeter. After I idled the engine for a few minutes to warm it up, the multimeter shows a steady voltage of 0.4V. But ...
Asker's user avatar
  • 113