# What the hell is wrong with my vehicle? **URL:** \ **Category:** Factual Questions\ **Created:** [March 4, 2008, 12:57am UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981 "2008-03-04T00:57:45Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![danceswithcats](https://avatars.discourse-cdn.com/v4/letter/d/9e8a1a/32.png) [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)\ **Post date:** [March 5, 2008, 1:17am UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/21 "2008-03-05T01:17:41Z")
[QUOTE=Rick] No don’t [redneck](http://www.snopes.com/autos/techno/fuse.asp) the repair. Re **check** the repair. [/QUOTE] You’ve rednecked the repair when you say the hell with it-put it on blocks and sell the tires to Bubba for a case of beer or two, and the truck is still in your yard 30 years later. ---
**Author:** ![messed\_up\_truck](https://avatars.discourse-cdn.com/v4/letter/m/f6c823/32.png) [@messed\_up\_truck](https://boards.straightdope.com/u/messed_up_truck)\ **Post date:** [March 5, 2008, 3:50am UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/22 "2008-03-05T03:50:39Z")
Injectors work, and fuel is reaching the engine, spark plug shocked the hell out of me, but it is working, i replaced the crank shaft sensor earlier today ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [March 5, 2008, 4:07am UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/23 "2008-03-05T04:07:34Z")
OK, you got spark, you got fuel. Now you are left with: Air, and At the right place At the right time In the right amount Did you double check that all of the air trunks are installed correctly? Are you 100% for sure you got the cam timing right? Did you re-check it? If not why not? Did you get all the sensors reconnected correctly? Did you re-check them? If not why not? What caused the head gasket to blow? Did the engine overheat? If so it might be a bad engine coolant temp sensor. Have you taken a compression test? What do the spark plugs look like after trying to start the engine? Wet? or Dry? ---
**Author:** ![messed\_up\_truck](https://avatars.discourse-cdn.com/v4/letter/m/f6c823/32.png) [@messed\_up\_truck](https://boards.straightdope.com/u/messed_up_truck)\ **Post date:** [March 5, 2008, 4:12am UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/24 "2008-03-05T04:12:48Z")
The engine is not overhead cam Do not know why head gasket failed, temp never got over 175 in my dash Spark plug is damp after attempting to crank engine Air trunks are installed correctly Compression Test? tell me more ---
**Author:** ![danceswithcats](https://avatars.discourse-cdn.com/v4/letter/d/9e8a1a/32.png) [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)\ **Post date:** [March 5, 2008, 5:47am UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/25 "2008-03-05T05:47:02Z")
[QUOTE=messed\_up\_truck] The engine is not overhead cam Do not know why head gasket failed, temp never got over 175 in my dash Spark plug is damp after attempting to crank engine Air trunks are installed correctly Compression Test? tell me more [/QUOTE] A compression test is done with either a diagnostic analyzer, or a compression test gauge. Remove spark plugs, thread adaptor into #1 plug hole, attach gauge, crank engine for ~ 10 seconds, record reading, lather, rinse, and repeat for remaining cylinders. [Here’s a picture of one](http://www.actron.com/product_detail.php?pid=16170). Buy it at Sears, Pep Boys or other auto parts chain store-some places may rent them by the day if you don’t want to spend $50. Helps tell if the valve timing is on, if valves and seats are in good shape, general condition of rings, etc. Given that you have a base spec for a new engine, compression will drop over time as a function of internal wear. One or two cylinders with dramatically different readings can point to problems such as cracked block, cracked head, broken ring, etc. ---
**Author:** ![Oslo\_Ostragoth](https://avatars.discourse-cdn.com/v4/letter/o/a9a28c/32.png) [@Oslo\_Ostragoth](https://boards.straightdope.com/u/Oslo_Ostragoth)\ **Post date:** [March 5, 2008, 6:49am UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/26 "2008-03-05T06:49:02Z")
[QUOTE=Rick] Ok, to get your truck to run you need three things: Fuel Air Spark You need those three things at the right place, at the right time, and in the right amount. [/QUOTE] [nitpick] and compression[/nitpick] ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [March 5, 2008, 7:04am UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/27 "2008-03-05T07:04:50Z")
[QUOTE=Oslo Ostragoth] [nitpick] and compression[/nitpick] [/QUOTE] compression is a subset of air as in the correct amount. If you don’t have compression you won’t have the correct amount of air in the cylinder. 😃 ---
**Author:** ![messed\_up\_truck](https://avatars.discourse-cdn.com/v4/letter/m/f6c823/32.png) [@messed\_up\_truck](https://boards.straightdope.com/u/messed_up_truck)\ **Post date:** [March 5, 2008, 7:59pm UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/28 "2008-03-05T19:59:20Z")
yeah bought a code reader today, it’s not throwing any codes guess i’ll try and get a compression tester ---
**Author:** ![messed\_up\_truck](https://avatars.discourse-cdn.com/v4/letter/m/f6c823/32.png) [@messed\_up\_truck](https://boards.straightdope.com/u/messed_up_truck)\ **Post date:** [March 5, 2008, 9:56pm UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/29 "2008-03-05T21:56:22Z")
Ok so i found out that my oil fill tube and gasket had come off, i read somewhere that you engine must read a minimum oil pressure in order to start, but i don’t know if a dislodged fill tube would cause low oil pressure. ---
**Author:** ![A.R.Cane](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@A.R.Cane](https://boards.straightdope.com/u/A.R.Cane)\ **Post date:** [March 5, 2008, 10:02pm UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/30 "2008-03-05T22:02:24Z")
There are better mech’s than me here, but I think if the compression was so low as to prevent the engine from starting you would have known it long before now. Have you tried the ether? Use it sparingly, but if you’ve got spark and the timing isn’t too far off, it _will_ start on ether. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [March 6, 2008, 12:34am UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/31 "2008-03-06T00:34:30Z")
OK, if the plugs are wet then fuel is getting into the cylinders. Let’s go over some basic stuff. How long did the truck sit from when it was last driven? Gas will get old and hard to light. How does the engine sound when you crank it? Normal? Slow? fast? Uneven? backfire? Spit back? Have you re checked all the sensor connectors? When you pull the plugs out, what do the tips smell like? Gas or something else? ---
**Author:** ![messed\_up\_truck](https://avatars.discourse-cdn.com/v4/letter/m/f6c823/32.png) [@messed\_up\_truck](https://boards.straightdope.com/u/messed_up_truck)\ **Post date:** [March 6, 2008, 12:49am UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/32 "2008-03-06T00:49:21Z")
Tips smell like gasoline, and i tested compression and it is good, i put new gas in it plus it only has been not running for about a week, when i crank it everything turns over but it doesn’t start, no combustion. All sensors are connected and code reader is showing no codes. ---
**Author:** ![A.R.Cane](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@A.R.Cane](https://boards.straightdope.com/u/A.R.Cane)\ **Post date:** [March 6, 2008, 1:01am UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/33 "2008-03-06T01:01:16Z")
Two things: When you checked the spark against the block, did you get a bright blue arc, or a weaker yellow one? (if you have to check it again, use a heavy rubber glove, or a pair of insulated pliers). If everything else is checking out, I’d guess the timing is way out. Again, it would be worthwhile to try the ether, _sparingly!_ ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [March 6, 2008, 1:03am UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/34 "2008-03-06T01:03:14Z")
[QUOTE=messed\_up\_truck] Tips smell like gasoline, and i tested compression [/QUOTE] Please define good. What are the numbers for each cylinder? ---
**Author:** ![messed\_up\_truck](https://avatars.discourse-cdn.com/v4/letter/m/f6c823/32.png) [@messed\_up\_truck](https://boards.straightdope.com/u/messed_up_truck)\ **Post date:** [March 6, 2008, 1:07am UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/35 "2008-03-06T01:07:37Z")
they were all right around 110 no major deviations ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [March 6, 2008, 1:31am UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/36 "2008-03-06T01:31:24Z")
110 is not what I would call good, but it should be enough to start the engine, assuming your compression gauge is accurate. If it is reading high, there might not be enough compression to start the engine. OK, try this. take each spark plug out and squirt a squirt or two of engine oil in each cylinder and then retake the compression test. Post the results for each cylinder. The spark plugs will not fire if they are wet. Either buy new ones, or clean and let these dry with some carb spray or brake clean. ---
**Author:** ![messed\_up\_truck](https://avatars.discourse-cdn.com/v4/letter/m/f6c823/32.png) [@messed\_up\_truck](https://boards.straightdope.com/u/messed_up_truck)\ **Post date:** [March 6, 2008, 1:35am UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/37 "2008-03-06T01:35:59Z")
All of the specifications i looked up said it should fall between 100-120, but i’ll give what you said a try in the morning when it gets light outside ---
**Author:** ![A.R.Cane](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@A.R.Cane](https://boards.straightdope.com/u/A.R.Cane)\ **Post date:** [March 6, 2008, 9:13pm UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/38 "2008-03-06T21:13:31Z")
Well, didja’ get her running? Inquiring minds want to know! ---
**Author:** ![messed\_up\_truck](https://avatars.discourse-cdn.com/v4/letter/m/f6c823/32.png) [@messed\_up\_truck](https://boards.straightdope.com/u/messed_up_truck)\ **Post date:** [March 6, 2008, 9:19pm UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/39 "2008-03-06T21:19:19Z")
Not yet, all i can assume is that my timing chain is bad or some how the crankshaft timing is off so i’m opening her up now to take a look…if i can beat the rain ---
**Author:** ![A.R.Cane](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@A.R.Cane](https://boards.straightdope.com/u/A.R.Cane)\ **Post date:** [March 6, 2008, 9:27pm UTC](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981/40 "2008-03-06T21:27:04Z")
Timing would be my best guess, good luck! [Previous page](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981.md?page=1) [Next page](https://boards.straightdope.com/t/what-the-hell-is-wrong-with-my-vehicle/439981.md?page=3)