Archive for the ‘Vehicle Tips’ Category
Posted on January 9, 2012 - by Richard
My ATS Video: Auto Repair Estimates and Troubleshooting Car Problems
Here is a tool how you can validate if your auto car repair estimates are good or not. This will help you prevent garage rip-offs by using email. This video described my comprehensive troubleshooting database so fixing car problems is a breeze. (Most of you have seen this already at Utube but I am trying to improve it with a new software I bought 2 weeks ago. Hope this is the last revision).
http://youtu.be/Xi_w6c7pVoE
Posted on November 21, 2011 - by Richard
2000 Chevrolet S10 Pickup Emission
Symptoms for 2000 Chevrolet S10 Pickup emission:
Got a complaint from a guy from ATS with a 2000 Chevrolet S10 Pickup emission. It has a 4.3L engine and came in with a check engine light on. He got initially codes p0172 and p0175 having both banks 1 and 2 rich fuel mixture. He checked the fuel pressure and got above 55 psi which was not bad. While monitoring the scanner display monitor live stream, he noticed the fuel trims were way high which were about -21 respectively for both cylinder banks.
Knowing the ecm was telling the fuel injectors to add more fuel, he tried removing the pcv valve hose to make the fuel mixture lean. Final fuel trim came down to -10 to both cylinder banks. This is what he ended up checking and asking ATS how to fix it. He was reluctant to remove the intake plenum since it was a major job.
Analysis for 2000 Chevrolet S10 Pickup Emission:
The fuel mixture here is rich but there are few causes for this problem:
1.) Leaking fuel regulator valve located under the top engine intake plenum which connects to the fuel rails. This fuel rails feed all the injectors. Unfortunately, these fuel connections are hard to access. This leads us to the next step.
2.) Leaking fuel injectors can also do this and this can be scanned using the injector balance test. Each injector is cut off and engine fuel trim are observed every time and compared. Once a faulty injector is detected, the intake plenum can be removed to check the affected injectors. At the same time, test also the fuel regulators for leaks if it needs replacement.
3.) Defective oxygen sensors and this can be monitored also using a scanner live data stream. If the sensor is stuck at rich or lean position, it can upset the ecm to make a false command to the injectors. Oxygen sensor is normally changed at regular interval especially a faulty code would show it. In this case, the oxygen readings were normal as per his report.
4.) The final approach that can be used to check this emission problem is to do a step by step test of the fuel system including the evaporative system. This latter system monitors raw fuel coming from the fuel tank which is vented or purged back to the fuel injector lines. Using the vent and purge solenoids, and gas tank fuel sensor, it prevents raw gas vapor to leak from the vehicle to pollute the environment.
A complete pinpoint test is used to analyze this problem which can help a mechanic or ATS member decide which part of the evaporative system is bad. This pinpoint test is available from ATS which are supplied upon request to all ATS members.
Final Fix for 2000 Chevrolet S10 Pickup Emission:
A pinpoint test was received by this ATS customer which lead him to replace the purge solenoid of the evaporative system. Once replaced, the engine fault code was reset and code never returned.
Additional tip for 2000 Chevrolet S10 Pickup Emission:
1.) To prevent replacements of unwanted parts or major labor jobs, get a good scanner and checked with ATS. This will help get huge savings from garages who charged $100 per hour or more.
Thanks,
Richard
Posted on November 15, 2011 - by Richard
2002 Dodge Caravan Emissions Problems
Symptoms for 2002 Dodge Caravan Emissions Problems
Do you have a fix for 2002 Dodge Caravan Emissions Problems? I got a call from an ATS member because his vehicle was using too much gas. The vehicle has been in 2 garages and they can’t seem to fix the problem.
In the last 3 months, the following were done: complete tune up like replace spark plugs, air and fuel filters and lately the ignition coil packs. They also flushed the injector system to make sure all injectors are clean. After all these jobs, the emission was still high because he was still using lot of gas.
In desperation, he got himself a good scanner and contacted ATS when he found he got a code P0172. Aside from this code, the fuel trim was -25 and the oxygen sensor reading was stuck or not fluctuating as normal. Doing a closer inspection, he did a compression test and all cylinders were ok.
However, he found out that cylinder 1&5 has fouled up spark plugs. After cleaning the plugs, he scanned again the injector wave pattern and found out the injector 1&5 looks like erratic compared with other cylinders. Are these injectors the cause of high emission?
Important Notes for 2002 Dodge Caravan Emissions Problems:
P0172-code means engine fuel system rich, full lean trim
Normal LTFT is between +- 10, -25 mean rich fuel mixture because of bad fuel system (injectors?)
Engine size for this is 3.3L with 1 injector per cylinder using ignition coil packs (no distributor)
Diagnostic for 2002 Dodge Caravan Emissions Problems
Looking at the information given here about the vehicle, it is clear that the culprit is coming from the 1&5 injectors and its circuit. The recommended way in checking this is to use a scanner so the injector wave pattern can be seen.
If the injector pattern deviates from other injectors, try this: look at the ecm wiring diagram for injectors 1&5 and check all the connections upto the ecm terminals. On closer analysis, the ecm driver for both 1&5 injectors is common for both injectors. To test the wirings, disconnect one of the injector plug in terminal and see if the other injector wave pattern changes. Do the same on the other injector.
Assuming both injectors will not show any change in wave pattern, does a resistance check between the injectors and ecm wiring harness. If resistance is lower than 5 ohms, then we know the injector harness is OK.
You can also measure the total resistance of each injectors 1&5 and they should be the same as per vehicle’s requirements (or call ATS). So if the harness is good and the injectors are good which were replaced by the last garage, it’s a safe bet the real problem lies in the ecm. A power and ground supply test will verify this.
Final fix for 2002 Dodge Caravan Emissions Problems
When the vehicle was tested using this ATS information, it was discovered that the ecm has an internal driver’s problem. A new rebuilt ecm fixed the problem.
More tips for 2002 Dodge Caravan Emissions Problems:
1.) The easiest way to check hard to find poor emission problems is to use a scanner with live stream data so you can see what the engine is doing internally. If you couple this with ATS wiring diagrams and instructions given by ATS, there is a good possibility that this difficult emission problems can be solved.
2.) Don’t forget your troubleshooting basics when testing engine integrity: vacuum intake and exhaust reading, fuel pressure test, cylinder compression test and making sure you scanned for codes. Getting a fault code will direct you to the specific engine circuit instead of wasting your time in time and parts that you don’t need.
Thanks,
Richard
Posted on November 12, 2011 - by Richard
97 Chrysler Town & Country Mileage Problem
Symptoms for 97 Chrysler Town & Country Mileage Problem:
My neighbor’s 97 Chrysler Town & Country Mileage problem was reported to ATS for advice. It has a 3.8L engine and the vehicle was bought since it was new. According to them, it’s been a while since their mechanic did a tune up and they felt that lately that the engine is running rough.
During yesterday’s check up, the mechanic took the fault code and got P0300 random misfire code. He tried repairing some leaky vacuum hose but the engine was still running rough. He also got the same P0303 code. Thinking that he had a bad #3 cylinder, he took the cylinder #3 compression reading and it was normal. The same compression reading goes for the rest of the engine cylinders.
Thinking the problem was not mechanical; he replaced the ignition coil pack and finally, replaced the egr valve which might be sticking intermittently. The code P0303 came back and this is where he got stuck. My neighbor now is now asking me how to help his mechanic. After all the things the mechanic did, what other reasons could cause a P0303 which result in having an engine with bad mileage?
Diagnosis for 97 Chrysler Town & Country Mileage Problem:
Fixing this 97 Chrysler Town & Country Mileage needs a complete analogy of this P0303 fault code which can be caused by:
1.) Bad or worn cylinder but compression test showed it was good.
2.) Bad ignition coil which he replaced already.
3.) Sticky egr valve which can cause the fuel mixture to run lean and was replaced already.
3.) Bad fuel injector or defective injector wiring connections.
In all probability, it is safe to explore the 4th option. I would start by checking the injector signal in cylinder #3. Using a noid light, you can disconnect the #3 injector plug in and connect the noid light tester. When the engine is crank, you should see the noid light blinking. If it does, injector circuit is fine.
To check, test and compare the rated resistance of the injector windings. Otherwise, the we need to check the injector wiring circuit from the ecm upto the injector plug in. You should get a resistance not higher than 5 ohms or you have a short or open connection in the wires. To do this properly, you need a complete wiring diagram of the ecm circuit from ATS.
Assuming the noid light is blinking OK and the same goes for the next 2 cylinders, I would go to the removal of the injector itself. This requires the removal of the intake manifold so you can access the injector. Once the injector is out, a proper inspection is in order or… if the entire injector fuel rail can be lifted with all the injectors intact; crank the engine and see which injector is leaking. A bad injector will drip all the time while the good ones will have a quick spray and shut off.
Final fix for 97 Chrysler Town & Country Mileage Problem:
When the mechanic got hold of this information, he removed the intake and lifted the injector fuel rail with all the injectors. During cranking, he found #3 injector is leaking. After removing the injector, he also found that the injector inlet screen was full of debris. When he informed ATS about it, we informed the source of the debris: dirty or corroded fuel tank.
To correct this, the tank has to be removed along with all the fuel lines/rail to be blown by air. This clean up process also needs the replacement of the fuel filter and all injectors because of the fuel contamination. Three days after we told him about it, he reported the engine was running smooth as if it was brand new. No codes returned.
More tip for 97 Chrysler Town & Country Mileage Problem:
1.) The egr can be tested using a scanner by using the LTFT and STFT features which are the fuel mixture indicators of the engine management system. The safe % range value is +10 for LTFT and -10 for STFT. This can be observed during idle.
Using this feature can avoid the unwanted replacement of the egr valve. This is also the best way to save in vehicle cost if you have your own scanner in situations like this. Using scanner with multiple features like “live data stream” monitor will help you pinpoint the problem right away.
Thanks,
Richard
Posted on November 11, 2011 - by Richard
2004 Chevrolet Silverado HD Poor Mileage
Symptoms for 2004 Chevrolet Silverado HD Poor Mileage:
This 2004 Chevrolet Silverado HD poor mileage problem happened to my ATS customer after buying this truck from an auction lot. When he first saw the truck, the exteriors were in great shape and had a diesel engine on it. The selling price was a little bit low but it had over 100k miles on it. He bought it on the spot but while driving it home, the truck started missing and cannot ran over 25 mph.
Since the auction lot gave him a good deal, he felt there was a hidden reason for the low price. He had it towed to the dealer and after paying $300 and 24 hours later, they could not figure the problem and wanted more money. Since he was a retired diesel mechanic, he took upon himself to fix it in his backyard. A week later and after spending lots of aggravations and $450 on parts, he joined ATS and asked for help.
Initial Tests of 2004 Chevrolet Silverado HD poor mileage:
1.) Won’t run higher than 25 mpg and has lots of white smoke in the tail pipe.
2.) Checked for codes but none found
3.) Replaced fuel filter and fuel pump
Diagnosis of 2004 Chevrolet Silverado HD poor mileage:
When I read this 2004 Chevrolet Silverado HD poor mileage problem, the first thing that I asked was: Did you check the diesel basics? This means checking the following:
1.) What is the engine compression? This is important because his symptoms showed incomplete combustion as shown by white smoke. A good diesel engine compression tester should have at least 400 psi cylinder pressure with the compression gage hooked up at the glow plug holes (see the diesel compression tester picture shown above).
2.) Are all fuel injectors working? The spray pattern can be checked at glow plug holes while cranking. Injectors should spray a little then quit should be normal. A constant spray while cranking means the injectors are leaking.
Notes when testing diesel injectors:
The ignition relay must be disconnected when doing this test to prevent the engine from starting. An ATS diagram should be used in order to locate the ignition relay.
3.) The fuel pressure should be monitored and compared for each cylinder. All pressure reading should be similar otherwise, check the fuel pressure regulator and fuel relief valve. When testing for fuel pressure, it should be done with engine idling. If you have a live data scanner, each injector can be killed to compare each cylinder performance.
4.) There are other basic tests and they include verifying the vacuum pressure at idle, cylinder leak down test (see previous blog or ask ATS), fuel hold down pressure, etc.
Final Fix for 2004 Chevrolet Silverado HD poor mileage:
After giving him all these repair suggestions, he found that half of the engine cylinders did not have any compression reading at all. When he opened up the valve cover, he found the push rods were bent. This usually happens when trying to start this engine during cold weather and using lots of ether starting spray.
More Tips for 2004 Chevrolet Silverado HD poor mileage:
1.) Never buy any vehicle no matter how cheap unless inspected by a certified shop or mechanic.
2.) Most auction car lots are also victimized by some scrupulous owners who deliberately sell a vehicle with big problems. This is why when going to auction lots, always go there a day ahead so you can check the vehicle you are bidding for. If you are not a mechanic, take one with you when you visit the auction lot.
Thanks,
Richard
Note:
ATS has lot of files for 2004 Chevrolet Silverado HD poor mileage FIXES so you can do it yourself. Just because it is a diesel engine, it is hard to fix. Troubleshooting basics are the same. Find out more from ATS now!
Posted on December 27, 2009 - by Richard
Saving Money When Fixing 2003 GM Emissions
Symptoms:
Fixing 2003 2003 GM emissions became available to me when I helped my buddy worked on his Sierra 1500 truck 2 weeks ago. The engine was misfiring, would barely idle and the check engine light was on all the time. It had a P0300 code on his scanner which denoted engine random misfire. He did a major tune-up by replacing all the spark plugs, plug wires, distributor cap and rotor. A quick compression test on all cylinders showed reading between 140-160 psi (normal). The main question is: how can you fix this without spending too much money?
Vehicle Specs:
2003 GM Sierra with 4.3L 6 cylinder engine with 4 speed electronic tranny, a multi-port fuel injection system and obd2 complaint.
Diagnostics for Fixing 2003 GM emissions:
Fixing 2003 GM emissions for me starts with using my $200 scanner and monitor the live data so I can view what exactly is happening inside the engine.
Scanner monitor live readings:
Engine at Idle:
Engine at 2500 rpm:
Tips in fixing 2003 GM emissions:
When checking for readings in the scanner live data, look for un-even reading between engine banks. Comparison can be made when engine is idling and when the engine is rev up at 2500 rpm.
I noticed the a defined fuel rich mixture concentrated in one bank only. This I observed when bank 1 kept adding fuel and bank2 kept subtracting fuel.
Final solution to Fixing 2003 GM emissions:
When fuel is concentrated in one bank, this usually denotes a blockage in the exhaust system. Using a vacuum gage, I got a high back pressure reading when tested. To do this vacuum test, rev up the rpm to 3000 rpm and take vacuum reading. A reading higher than 6 psi denotes exhaust restrictions. Dropping the catalytic converter (CAT) connections and retesting the fuel trim showed it returned to nomal which is lower than 10 percent. Replacing the CAT fixed the problem.
Thanks!
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